All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Mick: Only you know why you make yourself "put up" with receiving only the Public Service channels from Stroud!!
The reason is because the Commercial broadcasters do not have a "Public Service" obligation. They operate on a profit-driven basis and the cost of including over a 1,000 small transmitters in their portfolio would outway the benefit (as far as they are concerned).
The 81 transmitters that carry the Commercial multiplexes are the largest, by viewer population. This achieves 90% coverage of the population. To include the 1,000 plus relays would roughly double the cost of transmission whilst only adding about 8.5% of the population to the Commercial broadcasters' viewer bases. Clearly they don't see that as a worthwhile investment when they are in the business of selling advertising to generate revenue. That is, they don't consider the additional number of viewers to be worth the cost as far as attractiveness with advertisers is concerned.
It is unfortunate that the Stroud transmitter uses channels that are interleaved within the Commercial channels from Wenvoe as you could have had a second aerial installed on Wenvoe and combined them into one downlead to give you no Welsh programmes and the Commercial channels.
If you provide your location, preferably post code or nearby post code, then we might be able to suggest what the likelihood of receiving from another transmitter might be. The Slad transmitter covers a small area as it is only 2W, but it does broadcast on channels that could be combined with those of Wenvoe (if there is a location where both can be received).
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Rog: The three Sandy Heath COM multiplexes are "out of group" as far as the old four analogue channels are concerned.
This means that where such an aerial is fitted, its senstivity at the frequencies used by the COMs will be less than that of the other (Public Service) channels.
The four analogue channels were on Group A channels (frequencies). Group A is the bottom third of the band. Consequently, Group A aerials were fitted whose sensitivity is best on those channels and drops off on higher channels.
The COMs are at the high end of Group B and this Group is the middle third of the band.
Prior to 9th May, COM4 was in a channel in Group A, so such an aerial would probably have worked.
A Group A aerial isn't forced to mean no reception of the COMs. It will mean at least lower strength being indicated on those channels, but with digital strength isn't so important (it's quality that matters).
So long as the signal is strong enough to be above the threshold that the receiver requires to resolve a picture, then it will work. And so long as it is far enough above that threshold that any natural reduction in strength (e.g. caused by the weather) doesn't put it under, then there will be reliable reception.
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COM4 is on UHF channel 51, COM5 is on C52, and COM6 is on C48.
If your receiver has manual tuning, then try manually tuning to these three UHF channels. Some devices give more clues than others. Some will give a strength for a chosen channel and if yours works like that, then it might say that there is a signal there, but that it is too weak to resolve a picture. Or it might be sufficient and allow you to add missing services.
If you have more than one receiver, then it might be worth trying others due to the different functionality of devices that I mentioned.
You could try doing this with and without the aerial fed through other device(s). For example, if you have a TV with built-in Freeview and a Freeview box (e.g. recorder), then try tuning the TV with the aerial looped through the recorder and then with it directly to the TV.
Once you have a device tuned, then don't retune it if you then get "no signal" on some or all COM channels (e.g. if you change the configuration of the aerial leads). In that case the receiver is tuned and it is an issue with the signal fed to it.
If you have a booster, then try with and without. The stronger strength of signals after switchover means that some boosters are not needed now, and if used could give too much signal. With digital, too much signal will be indicated by receivers as low or no signal (just the same as low or no signal).
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Chris: The Northern Ireland Mini-Multiplex that will carry RT will come on air at the completion of switchover on 24th October.
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Brian: There has been engineering works in preparation for switchover.
Don't retune if you have difficulties as these won't be caused or resolved by retuning and you may end up loosing affected channels from your receiver altogether.
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Laura: I had a look at your road on Google Streetview and can see that residents have difficulty with reception. I couldn't spot a single aerial on the Brixham relay; all are on Beacon or Stockland.
jb38, KMJ,Derby, this would appear to be one where the predictor isn't very helpful, other than to indicate the directions of the transmitters.
Laura's road is lined by bungalows and is on a slope. Beacon Hill is in the direction up the slope and at the end of the road (the highest part) are two houses.
I don't think that there's much point in trying with a set-top aerial or piece of wire.
I suggest that you confirm that the channels tuned are those of the transmitter to which the aerial faces. The information as to which UHF channel is tuned is usually given on the signal strength screen.
For each of the following, check the UHF channel tuned to:
BBC One --- BH=C60; SH=C26; B=C43
ITV1 --- BH=C53; SH=C23; B=C50
BBC One HD --- BH=C57; SH=C29; B=C46
ITV3 --- BH=C42; SH=C25
Pick TV --- BH=C45; SH=C22
Yesterday --- BH=C51; SH=C28
BH is Beacon Hill, SH is Stockland Hill and B is Brixham.
As an example, go to BBC One and bring up the signal strength screen. Note which UHF channel it is tuned to. If it is 26, then the signal is coming from Stockland Hill. If your aerial points to Beacon Hill, then that needs putting right.
- If your aerial is on Beacon Hill and you find that you are picking up some or all signals from Stockland, then a workaround is to run the automatic tuning scan with the aerial unplugged up to 30% (or up to UHF channel 33 if it gives them during its scan). If you do do this, then having done so, check that you haven't picked up the two (or three) multiplexes from Brixham (by carrying out the procedure outlined above).
- If your aerial is on Stockland Hill and you find that you are picking up some or all signals from Beacon (or Brixham), then run the automatic tuning scan with the aerial plugged in and then unplug when it gets to 30% (or when it gets to UHF channel 33 if it gives them during its scan).
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Rog: I'm inclined to suspect that you have a Group A aerial and that it isn't sufficient for the out of group COM channels.
The solution is probably a replacement aerial of the "wideband" type. Alternatively, a second aerial for higher frequency channels, combined (using a diplexer) with your existing aerial.
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Rog: I can't explain why you may have received all channels; there would seem to be no logical explanation.
The full list of Freeview channels can be found here: DMOL Post-DSO Multiplex Channel Allocations
Those with a bullet and grey background in the "E" (England) column are those which apply.
Prior to 9th May, you could probably pick up COM4 because it was within the frequency range of your aerial (i.e. "in group").
COM5 adopted its current frequency on 23rd November and COM6 did so on 14th September (both last year).
With analogue, every transmitter used four channels. With the full Freeview service, there are six channels required. Most transmitters have been given channels that are within the range of frequencies that former analogue aerials are likely to work, which means that existing aerials will work fine.
In some cases, however, including with Sandy Heath, this has not been possible and hence aerials may need to be replaced.
The reason for the retunes is because not all transmitters switch at the same time and therefore in some cases there is a delay before certain channels become available. Some have restricted coverage and/or use temporary channels until their final one becomes available.
Following the retune on 9th May, COM4 is now on C51. The wait was due to the fact that Hemel Hempstead was using it until it switched over to digital in April.
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c macdonald: There is quite a bit of overlap of the signals from Moel y Parc and Winter Hill transmitters. Consequently it is not uncommon in your area for receivers to tune to the wrong one.
I would check that the receiver is tuned to Winter Hill for all channels and not Moel y Parc for some (or all).
On ITV4, bring up the signal strength screen and if it is tuned to Winter Hill, it will say that it is tuned to C55 whereas Moel y Parc is C48. It's possible but doubtful tjay you could be picking it up from one of two other transmitters on C29 or C50.
If you find that ITV4 it is not tuned to C55, then that is the problem if the aerial doesn't face Winter Hill which is east north east from your location.
As a workaround, try running the automatic tuning scan with the aerial unplugged up to 65%. If, after doing this, you are missing channels and your receiver has manual tuning, you may be able to restore them using manual tuning. For Yesterday,ITV4 and others, it is 55.
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c macdonald: My penultimate paragraph should say that if ITV4 is not tuned to C55, then that is the problem if your aerial DOES face Winter Hill.
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Rog, jb38: This is interesting and I think you are right Rog, to hold off getting a new aerial.
It may be worth a shot tuning to Sutton Coldfield for these services; you may be able to pick them up off the back of your aerial. They are:
COM4=C42
COM5=C45
COM6=C39
Or Waltham:
COM4=C29
COM5=C56
COM6=C57 (this one is doubtful as Oxford uses C57 as well)
Or Oxford:
COM4=C62
COM5=C59
COM6=C55
This might be worth a shot. Then keep trying 48, 51 and 52 to see if they are available.
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jb38: According to Ofcom, some of Sandy Heath's muxes are using the "S1 transitional antenna" until 27th June:
http://licensing.ofcom.or….pdf
These being PSB1, PSB2, PSB3 and COM6 (C48).
The others do not say that they are using that antenna; I'm not sure whether this means that they're not or that they are but it's not been mentioned.
Digital UK Tradeview says "PSB power-up" on 27th June. I wonder if this is related to the change of antenna as, according to DUK, the PSBs are at 180kW now.
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Mike Dimmick: Thanks for the explanation of the transitional antenna. It's very interesting.
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laura: You must be in a location where signals from more than one transmitter overlap one another.
When a receiver performs the automatic tuning scan, it "looks" to see what signals are available. In cases where if finds duplicate channels from different transmitters, it has to decide which to use. In this case it has decided to go with the BBC signal from a different transmitter. Duplicates are usually placed in the 800s.
In cases such as this, poor or erratic reception may ensue because the signal is being received from a direction other than that which the aerial faces.
It is sometimes possible to devise a workaround to this problem where the aerial lead is unplugged for the part of the scan of the frequencies that the offending transmitter uses. To know which part the plug needs removing, we need to know which transmitter is the desired one and which one is being picked up in error.
Knowing your location and direction of your aerial or the transmitter to which your aerial faces will be useful. Also, find out which UHF channels BBC One and ITV1 are tuned to. Do this by bringing up the signal strength screen whilst on each. Most receivers give tuned channel numbers there. This will allow us to work out which transmitters are being received.
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jmp: I should expect that the situation will improve.
The pre-switchover digital signals from Blue Bell Hill use the same frequencies as a number of other transmitters in that general part of the country. So if you happen to be in a spot that picks up a bit of signal from one or more of those transmitters, then they could act to degrade your reception from Blue Bell.
For example, Sandy Heath is co-channel with Blue Bell's current ITV1, C4, C5, ITV3 and others. The Digital UK predictor suggests that you might get a bit of Sandy's signal, and hence it "may" degrade your reception of Blue Bell.
After switchover the situation should improve as the power of Blue Bell will go up and there aren't transmitters in such close proximity that are co-channel (same frequencies).
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K Cooper: Dover is one of a few transmitters that, for its pre-switchover digital, broadcasts some multiplexes on different channels in different directions.
For example, Mux 1, which carries BBC One, BBC Two and some other BBC services, is on C68 and C45. It is not known which faces it radiates each, but I guess that one side will put it out on one channel and the other on the other channel.
There may be overlap, so you may be picking up the one that isn't quite as good for you.
Bluebell Hill uses C45 at the moment, so I would hazard a guess that C68 may be best for you.
What I suggest that you do is go to BBC One and bring up the signal strength screen. See if it tells you whether you are tuned to C68 or C45. Then do a signal check of the other (that you aren't tuned to). How you do this may vary depending on the device. You may have manual tuning or the signal strength screen may allow you to change the UHF channel number so as to "look" a different one. Or you may have to look in the 800s for another BBC One that is coming from Dover. Of course, they may not be one if you are in an area where there is no overlap.
It would also perhaps be useful to know what UHF channels ITV1 and Pick TV are coming in on as they have a similar dual-channel arrangement, them being 61/42 and 62/39 respectively.
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K Cooper: If you find that the other is better, then you will need to get them swapped. If you would like some help, then let us know which is best for BBC, and also which ITV1 and Pick TV seem to be the best as well.
It should be possible to have the aerial unplugged for part of the scan to avoid picking up the one you don't want.
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Ray: Yes, sometimes the automatic tuning procedure can leave the wrong transmitter tuned in.
Hannington and maybe Midhurst look as though they may be possibilities for you. Perhaps swapping to vertical polarisation would also reduce the likelihood of that happening as they are horizontal only.
Looking at the channel allocations for these transmitters, you should be able to unplug the aerial lead at 30% so as to scan Rowridge's channels and avoid those of Hannington and Midhurst.
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Colin Wardley: As previously advised ( Are you really watching free TV in high definition? | ukfree.tv - independent free digital TV advice ) Bluebell Hill does not broadcast HD until 27th June.
Therefore if you received it previously you must have been picking it up from another transmitter. Because this was likely to be off-beam for your aerial, reception was always expected not to be perfect. Therefore it may be hit and miss.
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SJ: Indoor aerials are hit and miss. Any aerial relies on being sited in a spot where it can get a signal and indoors (which is usually below the roof line where there are walls and other obstructions in the direction of the transmitter) is where the signal is less likely to be good.
The aerials in Jay Court point at Waltham, as do those on the main road.
I think that your chances of success with a set-top aerial aren't great because:
- There are three three storey (plus roof) buildings in the direction of Waltham, so they will be reducing the signal.
- The terrace that is parallel to Slack Lane is in the direction of the transmitter. Thus, the closer you live to the end where number 10 is, the more building you have in the way. Even a loft aerial is probably out of the question for the same reason. Conversely, the closer you are to the three storey buildings, the more you are in their shadow.
- If you live in the terrace that is at right-angles to Slack Lane, then you may have a greater chance for rooms that face the direction of the transmitter. Depending on the type of roof (whether it inhibits signal) you may be able to receive using a loft aerial.
All that said, I suggest that you look at extending the fixed aerial that serves your bedroom.
I would get proper stuff and not rely on the DIY kits. See A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial.
An unpowered splitter "may" work. Have a Plan B incase splitting the signal leaves you without sufficient. A solution in such circumstances may be a powered amplifier or perhaps feeding one outlet from another aerial and using the current one for only two outlets.
If you could receive Freeview using the fixed aerial before switchover last August, then you may be able to use a four-way non-powered splitter as the signal levels are now much higher.
With digital reception, signal strength isn't so much an issue; the objective isn't to get the signal strength bar as near 100% as possible. So long as the quality is 100%, then it the picture is as good as it will ever be. Different devices use different scales, so one's 50% strength is different to another's.
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Yvonne: As you probably know, Whitby is now poorly served by terrestrial television following the debacle in which the transmitter was resited to the back of beyond in 2007.
The Whitby relay transmitter will start broadcasting Freeview in September, but it will carry only Public Service channels. These are BBC, ITV1, ITV1+1, ITV2, Channel 4, E4, More 4, Channel 5 and the four HD services.
There will be no Dave, Film 4, ITV3, ITV4 etc. Only main stations such as Bilsdale carry these.
Is there a TV aerial and is it just satellite dishes that aren't allowed?
Where abouts is she thinking of moving?
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Deb: You posted the same message five days ago to which I posted a response:
My ITV/C4 Freeview channels have disappeared - what can I do? Is it my SCART cable? | ukfree.tv - independent free digital TV advice
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Brian Richardson: Confirm that Mux 1 is coming in on C52 by bringing up the signal strength screen.
If it is, then perhaps the post-switchover signal being fed into your receiver is too strong and overloading it:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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A D Woods: This one and the other Commercial multiplexes are on low power until 27th of this month when a retune will be required.
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david: This happens with some transmitters at switchover, where one of the analogue services takes the place of BBC Two analogue so as to throw another free.
C56 is not used at all by Dover after switchover as it is to be used by Sudbury for one of its Commercial multiplexes. These are on temporary channels at very low power which has caused many complaints from people who now can't receive them.
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P Kendrick: No because the Commercial broadcasters (those that don't transmit from Preston) don't wish to invest in almost 1,100 similar small stations.
They cover 90% of the population from 81 of the largest transmitters (by viewer population). To include the rest in their portfolio would roughly double their cost of transmission whilst only adding about 8.5% to their potential viewer-base.
They operate on a profit making basis only and have no "Public Service" obligation.
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An Irate Freeview viewer: See the report above from A D Woods citing the same problem over the last day or so.
Whilst there is never a guarantee, you will be expected to get these channels back once the power goes up on 27th.
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Richard: You're the third person to my knowledge that has reported an issue over the last few days about ArqB from Sudbury. This suggests that some (perhaps slight) change has been made at the transmitter.
This multiplex and the other Commercial ones have been running on very low power since last year. This one in particular has been difficult to receive for many people, although these have tended to be around the east and south of the transmitter (judging by reports on here).
There will be a retune on 27th of this month when these multiplexes will finally go on full power.
The manual tuning is asking for a UHF channel number, these being from 21 to 69. These are equivalent to the frequency on which the services are carried. Film 4 is on "logical channel number" 15 which is the number you key in to view it.
It the moment these services are on UHF channel 63. These are all one signal, known as a multiplex. Hence if you can pick it up, when you manually tune to C63, it would add all that this multiplex carries.
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Timmy K: It depends which transmitter is being received from. The Haywards Heath relay transmitter isn't likely to ever carry these channels because the broadcasters in question (the Commercial broadcasters) don't wish to pay for the 1,000 or so small transmitters to carry their services, probably owing to the fact that it will roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer-base. The current 81 transmitters achieve 90% coverage. They operate on a profit-making basis and have no Public Service obligation, unlike BBC, ITV, C4 and C5. For a more in depth explanation, see Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
For those homes that can receive from a station that broadcasts the Commercial channels, then they will be able to watch them, subject to them having an appropriate aerial.
As a test post code, I used that of the Haywards Heath Post Office, RH16 3XX, and put it into the Digital UK Tradeview predictor: Postcode Checker - Trade View
This suggests that full-service reception may be possible from Heathfield. (RH16 3XX)
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Anch: Wait until this Wednesday and ITV and other channels should become available. Only the BBC channels go to full power (and therefore become available to some for the first time) at the first stage of switchover. At the second and final stage, the rest go to full power (and become available for the first time for some).
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Jane Macaulay: Digital services are carried in groups known as multiplexes. You are missing multiplex "ArqB" aka COM6.
See here for a list of services and which multiplexes they are on:
DMOL Post-DSO Multiplex Channel Allocations
Yesterday, Film 4 and ITV4 are all carried on COM6.
The three COM multiplexes have been on very low power since switchover last year. The frequencies they use now are temporary until the perminant ones become available. Once the transmitters in Kent complete switch over on 27th of this month, the frequencies that Sudbury is due to use for its COMs will be available for use.
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Martin Raven: Some sets won't work after switchover due to the change in mode of the signals being transmitted. They were in 2k mode before switchover and are now in 8k mode.
Unfortunately some older sets weren't built to comply with the full DVB-T specification and 8k mode was ommitted.
If you post the model number of the device in question, we may be able to find out its specification.
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benard powell: It could be that the signal in the HDMI cable is interfering with that in the aerial lead. The lower ITV3 signal may therefore be more susceptible.
Try removing the HDMI cable completely.
Perhaps keep the two apart and/or use more heavily screened aerial lead.
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L Spinks: The reason is because the Commercial multiplexes from Sudbury are on low power and have been since switchover. They will go up to full power on 27th of this month when a retune will be required to restore them.
The wait has been necessary in order for the perminant frequencies to become available as they are used by transmitters in Kent until they switch to digital on 27th.
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I have finally sorted the problem with my loft aerial.
Since Emley Moor switchover last Semptember I've had an issue with the reception on my Sony RDR-HXD870. The picture was freezing for a second or so every so often. It was worst on the COM channels (maybe every 10 or 15 minutes on those).
I tried it with the Panasonic TU-CT41 set-top box and Hauppauge WinTV-HVR-900 USB stick turned on, with all three tuned to the same channel and only the Sony skipped.
The aerial was a 10 element wideband contract bought from Argos around 15 years ago. The downlead was 10 metres of solid-core coax with silver foil and 10 silver strands for screening. All this worked fine prior to switchover.
I replaced the aerial with a DM Log and the cable with Webro WF100, mounting the new aerial in the same place as the old one. It didn't make any difference.
I tried turning it a little off-beam and moved it further down the loft and the problem persisted.
There is another aerial in the loft which serves another room, and the Sony worked perfectly with it. This aerial looks like it could be a Philex SLx 32:
Philex Electronic (UK) Ltd. Homepage
My aerial was attached to an "L" shaped pole fixed to one of the rafters.
The solution was to use a straight pole fixed to the top of one of the joists so as to give more clearance between the sloping roof and the back of the aerial. Previously there was around a foot and now there are two or three feet. The aerial is therefore now a little further forward than it used to be.
Whilst the Philex aerial is also mounted on the rafters, which means it doesn't have much clearance between its back and the roof, it does have a very large reflector, so I guess that this was the reason why it worked.
Why might this problem have manifested itself with the post-switchover signal? (DN31NJ)
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The direction to the transmitter is about 30 degrees off being perpendicular with the ridge.
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ashley: I think that the most likely culprit is the Clennon Valley relay transmitter being only a couple of hundred metres from you.
What the reason is for this happening warrants further investigation. It depends on whether your aerial points to the adjacent Clennon Valley transmitter or the one on Beacon Hill:
1. If your aerial points to Clennon Valley, then it will be vertical. Check that BBC One is tuned to UHF channel 52 (this information is usually given on the signal strength screen). Likewise ITV1 should be C48 and BBC One HD should be C56. If these are correctly tuned to Clennon Valley, then I suggest that the problem is signal overload and you need to fit an attenuator inline with the aerial lead. The fact that you have high signal strength which drops to nothing at times suggests that your receiver could be being overwhelmed by the level of signal.
Clennon Valley does not broadcast the Commercial channels which include ITV3, Pick TV, Yesterday, Dave, Film 4 and others. If these are tuned in, then reception may be poor and they are coming from elsewhere.
2. If your aerial points to Beacon Hill, then it will be horizontal and pointing 34 degrees anti-clockwise of the Clennon Valley transmitter. The direction of Beacon Hill is 310 degrees.
With the aerial on Beacon, see if the receiver has tuned to Clennon Valley instead. Check the UHF channel that BBC One is tuned to by looking on the signal strength screen. Beacon is C60 whilst Clennon is C52. For ITV1, Beacon is C53 and Clennon is C48. For BBC One HD Beacon is C57 and Clennon is C56.
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Bob: On 12th BBC standard definition channels switchover to full power digital so if you don't retune on that date then you will be unable to view them.
On 26th the rest switch over.
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Alain: Can you manually tune to these three channels 50, 59, 55, and does your receiver give any indication of signal strength and quality when you do so? Different receivers are designed differently and some give more clues away than others so you might like to try different devices.
The only thing I can wonder is if you are picking up too much signal from another transmitter that uses these three channels, such as Midhurst because your aerial happens to be in a good spot for it.
As well as performing the above test, try a manual tune to C61 and C62 which are also used by Midhurst. See if these give any signal reading.
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Further to Colin's message, there are a number of pages that return similar Fatal errors. For example, Freeview:
https://ukfree.tv/s/?23=29
Fatal error: Call to undefined function getbloggoto() in /home/admintv/public_html/s/index.php on line 21
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Mike Dimmick: Thanks for the insight. I have some questions for you which I will be grateful if you can answer.
The PSB networks are different to the COM ones, coverage wise, with the latter being more restricted due to channels being re-used more often (distance wise from transmitters). I have seen that you have said that coverage is generally more often restricted by interference than propagation. Helping out on this site, I have seen a number of occasions where this has been seen to be so.
Some transmitters have COMs at the same ERP as the PSBs, but according to predictions, their will be some viewers who will only be able to pick up the PSBs. (See Freeview news | ukfree.tv - independent free digital TV advice )
Referring to the Arqiva "Reference Offer for the Provision of Network Access" (page 29), Emley Moor uses two sets of panels, one for PSBs and one for COMs. Both have an ERP of 174kW. Is it likely that the COMs antenna's beam is tilted lower than the PSB one (which might account for the difference in number of people served for each)? At my location, the COMs appear lower strength and turning the aerial off-beam, when the COMs start to break-up, the PSBs are still strong.
http://www.arqiva.com/cor….pdf
Then there are those whose COMs are at half-power to the PSBs. Midhurst is one such example and its Steyning relay currently broadcasts co-channel with two of Midhurst's COMs. This is an example which illustrates why the COMs are more restricted.
Midhurst isn't shown in that document, so take Stockland Hill as an example. It apparently uses one antenna system for all six muxes (all of which are in the 20s) and the COMs are at half the power of the PSBs.
Why do some transmitters have two antenna systems and some have one? I appreciate that where channels are far apart they are likely to have to have more than one. I presume that the tilt of the beam will be the same for Stockland's PSBs and COMs as it's the same antenna.
Is the answer to the question cost and the fact that there's little to be gained having different antenna systems with smaller transmitters and that reducing ERP is a much more effective (from a cost point of view) in restricting coverage?
Then there is Belmont. The PSBs are in the 20s at 150kW, COM4 is on C30 at 50kW and COM5 and COM6 are on C53 and C60 at 100kW each.
Obviously C53 and C60 can't have as big a footprint as the PSBs as these are re-used from Oliver's Mount, for example. Some in Filey receive from Oliver's Mount and some, including those low-lying on the sea front, receive from Belmont. So there is clear overlap.
The reason I mention Belmont is because of the apparent anomaly of COM4 being half-power to COM5 and COM6. Why is this?
According to the Arqiva document, the three PSBs and COM4 use one antenna system and COM5 and COM6 use another. This makes sense due to the channel spacings.
Is the reason that C30 is at lower power so that the signal doesn't carry as far (as it's being radiated from the PSB antenna)? And again, for cost reasons: instead of having three antenna systems; one for PSBs, one for COM4 (lower power and lower tilt that the PSBs) and another for COMs 5 and 6?
I am wondering if it is cheaper to restrict coverage by reducing ERP (for COM channels) whilst using the same antenna as the PSBs (e.g Midhurst, Stockland and Belmont COM4). But for the larger transmitters it is more financially viable to have two antenna systems, even where all channels are close to each other (e.g. Emley Moor and I presume Crystal Palace).
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Susab Bourchier: Without knowing where you are it's not possible to answer the question!
Midhurst broadcasts Film 4 and other Commercial channels, but their coverage is more limited than the Public Service channels of BBC, ITV1, Channel 4 and Channel 5. Thus, there are some who can only receive the Public Service channels and not the Commercial ones. In "some" cases an alternative aerial will allow reception of the Commercial channels.
If you provide your location, preferably in the form of post code or nearby post code (e.g. a shop), then a check can be made as to the likelihood of reception of the channels.
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Laura: It only six miles from the transmitter, the signal may be very strong. Consequently too much signal could be being fed to your receiver which is overwhelming it at times.
See Freeview news | ukfree.tv - independent free digital TV advice
Try fitting an attenuator inline with the aerial lead so as to reduce the level of signal. A 20dB variable one will allow adjustment. These can be obtained from online sources for £3 or £4.
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Peter: The answer depends on which transmitter you are using.
If you and your friend have your aerials directed to the Bury St Edmunds transmitter, then it doesn't carry these channels. It only carries the Public Service channels which are BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services.
If you provide your location, preferably in the form of post code or nearby post code (e.g. a shop), then likelihood of reception can be checked upon.
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Colin: You should definately have your aerial vertical as the Commercial channels aren't as strong horizontally. The marked difference in strength can be an issue.
You may have too much signal, what with the transmitter being only five miles away:
Freeview news | ukfree.tv - independent free digital TV advice
The Rowridge mast can be seen in the photographs taken by Google Streetview on Chale Lane:
PO38 2LE - Google Maps
And Atherfield Road:
PO38 2LE - Google Maps
What's the reason for a high-gain aerial? Perhaps you should turn it the other way and point it at France!
If your aerial is a wideband one, which a look on the Philex site suggests that all SLx 48 models are, then it will have less gain at Group A channels, of which all of Rowridge's are.
There's no such thing as a high-gain wideband yagi aerial that has "high-gain" on Group A channels. See these curves:
Gain (curves), Again
Thus a high-gain wideband yagi aerial used on Group A channels isn't so high-gain.
As all Rowridge's channels are in Group A, where a high-gain aerial is needed, then it is best to go with a high-gain Group A aerial.
That said, why is a high-gain aerial required at only five miles with apparently good line of sight?
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Alain: To a lesser degree you vertical aerial will pick up horizontally polarised signals.
I have to say that when I made my posting, I was probably clutching at straws with regards a possible explanation.
A terrain plot shows that you are 50 miles from Midhurst with a few hills in the way, so it is probably unlikely to be the cause:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
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Justin: I expect that it's just the lower power of the ITV signal. Wait until tomorrow and they will all be on full power!
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Farrah Day: I looked back at your previous postings to find that you are in Nuneaton and that The Wrekin is within a few degrees of Sutton Coldfield.
Have you confirmed that BBC One is tuned to Sutton Coldfield on C43 and not The Wrekin on C26? Likewise ITV1 should be C46 and not C23. HD services are C40 and not C30.
If you find that any of these are tuned to The Wrekin, run the automatic tuning scan with the aerial unplugged for the first 30% of the scan.
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Colin: If the problem is excessive signal, you may well have enough to distribute it to multiple rooms using an unpowered splitter:
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
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Stuart Mcfarlane: Where is your aerial pointing and which multiplexes are missing?
If it is Sudbury, then the Commercial multiplexes are on low power until 27th June when a retune will be required in order to restore them.
If they have manual tuning, try it. Or try taking them to a different aerial outlet and see if they work then, if it is convenient.
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Stuart Mcfarlane: See this page and identify which multiplexes are affected:
DMOL Post-DSO Multiplex Channel Allocations
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As engineers have to commute to relays, they can take longer to get back up and running, particularly if there's many of them.
Digital UK published the times at digitaluk.co.uk/heathfieldrelaytimes
Some relays are due to be back on mid-morning and others are due mid-afternoon.
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Mark Agius: The Channel Islands' transmitters are PSB-only. Only the three PSB tables on that page have a "CI" column, the rightmost in the COMs is "NI".
ITV3 is carried on PSB2 on the Channel Islands because there is no +1 variant for ITV Channel Television.
I imagine that the services that PSB2 carry are decided on the basis of which is likely to yield the most revenue from advertisers. So I guess that ITV1+1 and ITV2+1 are seen as more lucrative than ITV3 and ITV4, for example.
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D Williams: Because sadly that is the way things are going these days.
"Public Service" and "Universal Service" tend to be allowed to give way to profit-driven organisations.
The Commercial broadcasters which don't transmit from Cynwyl Elfed and over 1,000 other similar small relays can choose where to site their transmitters.
Due to them operating to generate profit by selling advertising, their interest is to have as many potential viewers as possible at the lowest possible cost. They broadcast from 81 of the largest transmitter sites (largest by viewer population) and achieve coverage of 90% of the population.
For them to include all the other relays would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer base.
The "Freeview Light" transmitters carry only Public Service Broadcaster services. The Commercial broadcasters don't have a Public Service obligation.
The hilly areas that require relays to fill in the gaps are worst affected. Wales is particularly badly affected, with the Highlands of Scotland and the Lake District also being poorly served by the Commercial broadcasters. See the map here Where are the public service (Freeview Light) transmitters? | ukfree.tv - independent free digital TV advice
Also see Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice for a more in-depth explanation.
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Dholder: Due to your close proximity to the high-power transmitter, I suggest that it could be too high a signal level which is overwhelming your tuner. See here for an explanation and solution which is to install an attenuator inline with your aerial lead:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
In the mean time, you may be able to restore service by reducing the level of signal. Try a 12 inch piece of wire or a set-top aerial maybe.
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daniel badman: Post code checkers should be used as a guide only. I view the predictor as a guide to *possible* likelihood of success.
They exist because of the demand from people for such a service. Signals aren't carried by Royal Mail and there are so many variables that could never be taken into account that they can't be perfect. A whole post code can have widely varying signal levels, local obstructions (buildings and trees) aren't taken into account. Neither are the properties of a viewer's aerial, which also affects reception. There are other variables....
Prediction of the weather is much the same thing, although perhaps there is more chance of techniques being improved with it.
I'm a little puzzled by the results that the predictor returns for TN35 5EF because at the top where is lists the transmitters it includes Hastings, but then below where is gives the prediction for each one that is listed it doesn't include Hastings. By the way, "Hastings Old Town" is a different transmitter to "Hastings".
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JVO: According to information from Ofcom, 27, 24, 21 and 48 are using the "transitional S1 antenna" until 27th of this month. This affects the signal in your general direction, so see how it goes after 27th.
This is so as to protect against interference with transmitters in the south east that complete switchover on that date, although I can't work out which one uses C48 until then.
If the change requires outdoor work (on the mast), then obviously it may be delayed due to the weather.
If you find that you get C48 from 27th, then let us know on here as it will help inform others who are in the same position. You may also like to make a note of the signal strengths on 27, 24 and 21 (HD) to see if they go up on the same date that 48 becomes available to you.
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Bill: The answer to the question can only really be found when the retune is attempted.
It might be worth pointing out that before switchover Heathfield was Group C/D and after it is Group B. In marginal areas such as yours, this "may" be an issue. Only when retuning is attempted will you know whether this is a problem; it is just something to be aware of.
Refer here for an explanation of aerial Groups: Aerials, TV Aerial and Digital Aerial
You will see that there is a bit of overlap between B (middle third) and C/D (top third). PSB1 and PSB2 are in the overlap region and PSB3 is on the channel immediately below the overlap (47). The COMs are below that.
So if there is going to be difficulty receiving any, it is likely to be the COMs which are those which Newhaven doesn't carry. There is the added fact that the signal type used by the COMs is less robust than the PSBs and this being so that they can get more services in. This comes at the expense of fringe viewers.
This said, aerials don't receive nothing outside of their Group; they drop off gradually. See here for some examples: Gain (curves), Again
I make this point so if you find this to be the case, then this may be the answer.
See here for a list of services by multiplex (those with bullets in the "E" for England column): DMOL Post-DSO Multiplex Channel Allocations
If this does prove to be a problem, replacement with a Group B aerial (on Heathfield) "may" be the solution.
You "may" be able to receive from Heathfield at your location. Of course, up to now there has been no difference in what could be received from either. Digital TV from Heathfield was out of the question and it didn't carry Channel 5. Where only the four analogue channels would have been receiveable so there was no benefit in struggling with Heathfield when Newhaven carried an identical service with much better signal.
Now that we have the two-tier terrestrial television transmitter network people are going to want to receive from full service transmitters where reception is marginal instead of a "lite" transmitter whose signal is good.
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John: Without knowing your location it's not possible to know the likelihood that this might be the case, but if you are close to the transmitter, your receiver could be suffering from too high a signal level which is overwhelming it at times. See here for an explanation and solution:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Doreen Birks: That is correct.
COM4 (SDN) from Heathfield remains on its pre-switchover frequency until 27th. This is due to its final frequency being used by transmitters in Kent until they switch-over on that date.
See this page: DMOL Post-DSO Multiplex Channel Allocations
Scroll down to the table for COM4 to see which services this affects. They are ITV3, QVC and others. If retuning isn't carried out, then these will be unavailable from 27th.
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Bill: One other thing about Heathfield; COM4 (SDN) which carries ITV3 etc (see the DMOL link I gave you) does not go to full power until 27th of this month so it is likely to be unavailable until then.
This is because its final frequency is in use by Kent transmitters until they complete their switchover on that date.
A full retune will be required then, or you may be able add it by manually tuning to C42. It will depend on the design of the receiver as to what it will allow you to do.
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Alain: Crystal Palace can't interfere with Hemel Hempstead because they are on different channels.
I have no idea what your problem might be. It might be worth searching the internet to see if others are in the same position.
There may be a firmware update for the device or there may be new drivers for it that will cure the problem.
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Daniel Badman: Thanks for the report; it's good to hear that you have it sorted.
Different devices use different scales and have different tolerances so you can't really compare one with another.
The objective with digital is to have good quality. There needs to be a strong enough signal for it to be above the threshold for a receiver to resolve a picture.
The picture produced with a 100% quality signal with strength of 65% is the same as 100% quality with 85% strength. If a booster is connected to increase the strength, then it should be removed. "If" the quality is an issue (i.e. you get break-up) without it, then it may need to be present, but if there is good quality without it, then don't use it.
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Liz English: All receivers should have to allow manual tuning. It is bad designers that are responsible.
What should happen is that they are locked in a room with 100 of the things and told to tune them all in correctly with the "real world" problem that you are experiencing. Then they should only be allowed once all that is done.
Are you sure that it doesn't have manual tuning?
My Sony RDR-HXD870 does but it's a bit hidden. Having tuned to programme channel, e.g. ITV1, you bring up the signal strength screen and that allows selection of UHF channel. The receiver having "looked" at that channel then allows the user to add any services that may have been found.
The tricky thing here is that Bluebell's pre-switchover ITV1, C4, C5 etc is in the 20s which is where all of Crystal Palace's are. You should be able to remove the aerial lead for the first 30% of the scan to miss out Crystal Palace. However, in so doing you will miss out Bluebell ITV1. If you can put up with that or if you have manual tuning hidden somewhere, then you may be able to add it using that.
The only thing I will say about manual tuning is what it does may vary from device to device. Because receivers usually put duplicates in the 800s, other transmitters within range are often tuned in. In some cases manually tuning then achieves nothing because as far as the receiver is concerned it is tuned (albeit in the 800s). Obviously the user wants the manually tuned channel to be the main one and not thrown in the 800s.
The trick may be to get it so that it doesn't store the mux from the wrong transmitter during the automatic tuning scan, perhaps by removing the aerial for all or part.
Failing that, you may find that BBC One from Bluebell is in your 800s. There may be a facility to swap services. I will be a pain to swap all the BBC ones, so you may just have to hope that you don't get much break-up because the wretched thing has tuned to CP.
The thing is that BBC from Bluebell is now on its final power. Crystal Palace switched in April, so you probably have never tuned since CP switched over which is why you've never had this problem before.
If you find that this is still a problem after 27th, then run the automatic tuning scan with the aerial unplugged until 30% and this will miss out CP. All of Bluebell's channels will be above CP's at that time, so this should sort it.
*Unless* perhaps it is one of those pesky pieces of junk that take it upon themselves to do a full retune at some point when unattended and therefore revert to CP. If there is an option to turn this "function" off (which there isn't forced to be) then it should be turned off. If this turns out to be a problem, then you will have to cross that bridge when you get to it.
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micky, Tony, Dave: SDN (ITV3 etc) remains on its pre-switchover channel 48 on low power until 27th June. This is because C42 is currently being used by transmitters in Kent until they switch-over on that date.
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Briantist: SDN remains on C48- until 27th at 2kW (according to DUK).
It has never used C42+ which is what Tunbridge Wells used before switchover and up to 27th. The other five muxes are a SFN with TW now. SDN's SFN doesn't start until 27th.
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Peter: You can avoid it tuning to Eastbourne by unplugging the aerial for the first 30% of the scan. However, if it is one of those receivers that takes it upon itself to due a full rescan when unattended and goes back to Eastbourne, then you will have to see if there is an option to turn off that "function". If not, then cross that bridge when you get to it, but the last resort would be to fit a Group A filter. This will block out all Group A channels which are those in the 20s and some lower 30s.
If this is an external aerial or perhaps a professionally fitted loft aerial, then it may be a Group A one which makes it not the best choice for Heathfield which is Group B now.
For an explanation of aerial groups, see Aerials, TV Aerial and Digital Aerial
They drop off gradually and so a Group A will still work to some degree on channels outside of group. For some example gain curves, see Gain (curves), Again
If this is a set-top aerial or one from a DIY kit, then it is probably a wideband one and will be more suited.
If you can, try using it without the booster to see if it is sensitive enough now. C48 (SDN which carries ITV3 etc) is still on low power until 27th when it will move to C42 and go up to full power, so it may be unavailable or intermittant now.
If you are looking at replacing your aerial, then I recommend that you take a look at ATV's site. It has a page on Heathfield:
Heathfield Transmitter
Heathfield was Group C/D before switchover and is now Group B, so if you do go for a group aerial, then it should be a "B".
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Micky: This is an independent site, thus information listed is sourced from elsewhere. Mistakes can happen and I have pointed this out to Briantist who is the site's owner.
One of the problems you may have is that C47 and C49 are high power and therefore strong signals, and relatively speaking, C48 in the middle is weak. This marked difference could be the source of the problem as the high power signals could be acting to desensitise your receiver. That is it is "looking" at 48 with high power signals on adjacent channels.
This could be likened to your eyes densitising at night when bright light is shone in your direction. Car headlights coming towards you, for example, may reduce your ability to see the surroundings.
You "may" be able to reduce the level of all signals by using an attenuator inline with your aerial lead in order to increase the sensitivity of the receiver. I say "may" because in so doing you will be reducing C48, but at 2kW at only four or five miles away is still powerful so you may be able to find a sweet spot where it all works.
If you get a variable one (20dB) you can then adjust it whilst viewing the signal strength on C48. Give it a few seconds to adjust to any change you make. Then find where it is at its maximum.
Attenuators can be picked up from online sources such as eBay or Amazon for £3 or £4.
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Peter: I should perhaps declare that my comments are made as a non-professional with an interest in the subject.
A Group A bandpass filter means that it allows through only Group A channels. A Group A bandstop filter (if there is such thing) allows through all except Group A channels.
There was (and maybe still is) a plan to sell off C31 to C37 for three new multiplexes. These would be likely to broadcast from the transmitting stations that carry the current three COMs. The Group B bandpass filter sold by ATV (and I assume all "Group B" BP filters) starts at 34 which could cause issues in the future.
I'm not sure whether this plan will come to fruition. It seems like the typical dogs dinner you get these days. Who knows, we could go back to having a single television channel in a few years time, so that most of the spectrum can be sold for 4G, 5G, 6G etc. Let us hope that it won't be Murdoch that will be in charge!
You can get notch filters which are used to stop a single channel. You would obviously need three (or a triple one if there is such a thing) for the three channels used by South Tower. I have no idea on cost so can't say whether that's worthwhile.
F-connectors are generally used in places where the connections are generally perminant and not likely to be unplugged by users. So in a loft or outside (with suitable weatherproofing) it's good practice to use F connectors.
There may be a control on the amplifier to reduce its level which might help. It's probably best to note where it was set originally just in case it goes pear-shaped.
I read your earlier postings which mentioned about a loft aerial. If this is the same one, then could you move it to somewhere where it will still be able to pick-up from Heathfield, but where it will get less signal from the direction of South Tower?
I re-affirm what I said about a Group A aerial being less suited to Heathfield and hence might need replacement. The colour system that is used denotes Group As with a red tip and Bs with a yellow tip. Widebands are black, although depending on its age, I wonder if it may, perhaps, not use any scheme.
I also wonder whether swapping it with a Group B would help a little to reducing the pick-up of Eastbourne (assuming that it is a Group A) as well as increasing sensitivity of Heathfield. Also, even though Group B officially goes down to C34 it should still work quite well on 31 to 33 should they ever get used.
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Micky: Generally speaking, most people shouldn't need a booster at such close proximity to the transmitter. I say generally speaking because I don't know whether there are local obstructions.
This was true before switchover when a set-top aerial may well have been sensitive enough at your location.
The main reason I would expect you to be using a booster is so as to distribute the signal to different outlets, although even then you may well have sufficient signal to split it.
As a matter of principle, I suggest that you only use a booster if it doesn't work without it and not the other way around. With digital reception, too high a signal level gives the same sort of effect as too little signal. That is the signal strength gets lower and when it is really high, the receiver becomes overwhelmed and shows "no signal".
So long as the quality is good at all times (no break-up) then you have the best picture you can get. If the strength is at 75% (for example) with good quality, then there is nothing to be gain from trying to push for 100% strength; only quality to be lost.
I'm not familiar with the Humaxes but I do know that some receivers have in-built boosters. Make sure that this is set to off.
If, having removed the booster, you find that C48 is still unavailable, then the solution "may" be attenuation, as I suggested above.
A set-top aerial should pick up less signal than your roof-top or fixed aerial (if you're using one). Or try a piece of wire about 12 to 18 inches long inserted into the inner part of the aerial socket. These may be temporary fixes to restore Quest etc until 27th, if nothing better can be found.
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Jonathan Smith: Portable aerials are always hit-and-miss because by their very nature they can be environments where the signal can vary all the time due to objects moving around them. Nonetheless, I would try and get into a position where I think that the chances of reception are likely to be the greatest.
Without knowing you location it's difficult make a suggestion as we don't know what the likelihood of reception might be. Perhaps you can give your location, preferably in the form of post code or nearby post code (e.g. that of a shop). Also, did you have digital reception before today? And what is the make and model of the receiver that you are using (either set-top box used to receive or TV with in-built Freeview)?
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Colin: Do you use a HDMI cable to connect the Humax to the TV? I know you said that it isn't a HD model, but they do have HDMI sockets on.
The signal in the HDMI lead might affect that in the aerial lead, particularly if they're close. The same goes for others such as USB leads and maybe ethernet leads.
Once it's tuned correctly, then leave it be as retuning will achieve nothing. You've done the right thing and checked that it is tuned to the correct channels. Your attention must turn elsewhere.
I'm not sure what likelihood there is of too much signal, but you should be aware that this appears the same as too little a signal. Remove any booster you may have. Try reducing the amount of signal by removing the aerial lead and holding the plug close to the socket but not quite in contact. Give it ten seconds to adjust and see if it goes up as you remove the lead. The objective being here to see if the level going into the tuner is excessive. Holding the plug close should help loose a bit. If this is the problem, as you start to loose signal the level should go up as the overloading of the tuner subsides, then as you loose more the strength bar will go down again the signal level is reduced (that is reduced for real this time).
Or maybe you will have to try moving it within the loft or it may be best mounted externally.
At your location you "may" be able to pick-up from Whitehawk to give you the full service. As your aerial is Group E this makes it suitable (assuming suitable gain). You may have to have it outside for this.
The only thing to be aware about Whitehawk is that it carries BBC South East (as Newhaven), but ITV Meridian from Southampton rather than Meridian Maidstone as you get from Newhaven.
Or Heathfield may be possible. As Newhaven is a relay of Heathfield, the regional programming is the same. It is also a Group B, so your Group E aerial will be suitable (again, assuming suitable gain).
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P Ricketts: Unfortunately it is not likely that Thetford will ever broadcast the Commercial services. They achieve a 90% coverage of the population by broadcasting from 81 of the largest transmitters (largest by viewer population). To include over 1,000 small relays, of which Thetford is one, would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer-base. As they operate on a profit-driven basis where they sell advertising, they want to get as many viewers as possible at lowest cost.
The channels that Thetford carries are the Public Service ones. The Commercial broadcasters have no "Public Service" obligation.
The best you can do is investigate the possibility of receiving from one of the transmitters that carries the Commercial channels.
For switchover, Tacolneston had a replacement taller mast built, so this will mean it will reach parts that it wouldn't previously.
As a test, I put the post code of the ACF Training Centre on Croxton Road into the Digital UK Tradeview predictor and it thinks that excellent reception from Tacolneston may be possible at that location:
Postcode Checker - Trade View
If reception is not possible from Tacolneston at your location, then you may be able to receive from another transmitter such as Sandy Heath and combine that with your current aerial on Thetford so as to give you your current Anglia East regional programming.
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Farrah Day: That's how it goes sometimes; and afterwards you find that the solution was at your fingertips all along!
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Colin: Maybe poor screening on the aerial lead or the aerial lead isn't making good contact with the plug on its end. Sometimes the strands of wire break next to the plug because of stress.
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Colin: If you are looking at DIYing, or just wishing to be informed before calling in a professional, see www.aerialsandtv.com
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Ian Farrow: Unfortunately it is not likely that Newhaven relay will ever broadcast the Commercial services. They achieve a 90% coverage of the population by broadcasting from 81 of the largest transmitters (largest by viewer population). To include over 1,000 small relays, of which Newhaven is one, would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer-base. As they operate on a profit-driven basis where they sell advertising, they want to get as many viewers as possible at lowest cost.
The Commercial broadcasters have no "Public Service" obligation.
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Adrian Bance: On the basis that you had 100% strength before switchover (which may suggest that it was bordering on the excessive then), I suggest that the problem is that the signal being fed into your tuner is now too high and is overwhelming it. High signal level has the same appearance of low and poor signal, that being that the signal strength deteriates and quality goes due to the distortion.
Payment of the Fee does not guarantee availability of signal or reception of signal. The reason for this increase is so that other Licence Fee payers can now receive the signals.
For an explanation of too much signal, see ukfree.tv - independent free digital TV advice
If you have a booster (and it isn't installed for the purpose of splitting the signal to feed separate rooms), then it does beg the question why when the signal beforehand was so strong. This should be removed.
If you don't have a booster, or if you've removed it and the problem persists, then fit an attenuator (probably a 20dB variable one) inline with the aerial lead to reduce the signal level.
This is an independent website, as it clearly states. The the information provided on it is obtained from official sources and simply reflects what those sources say. If they are wrong then it cannot be right.
I have just checked the BBC Reception site www.bbc.co.uk/reception and it reports no problems with Bluebell Hill TV. The BBC only reports on its own services.
The other source that this site uses is Digital UK and you can view the source information at www.digitaluk.co.uk/engineeringworks
Or underneath the text at the top of this page that says that there are no faults, click on "Click to recheck" and it will recheck those sources. Clearly as this site sources its information from third parties and those third parties don't notify the site when fault statuses change, then it is only going to change on here when it checks the sources again.
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Andy: Read my posting above to Micky which I made at 3:31PM today!
COM4 remains on low power until 27th of this month.
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Stuart heynes: This is a bit of a riddle as I can't understand what the problem is.
There are a number of possibilities:
1. If you've retuned the TVs, then perhaps you've only retuned the digital side of them. Having reset them, maybe it wiped the memory for analogue channels. What each does probably varies by design.
The objective of this first stage is to tune the TVs to the Sky box. Don't change the RF out channel on the Sky box.
What I would do is put the Sky box on analogue programme number 1 on each of the TVs. That is where you used to have BBC One analogue.
2. There is the possibility that one of the new digital signals in your area use C44 or adjacent channels which now makes it unuseable and therefore you will have to change the RF out on your Sky box.
You have asked about retuning the Sky box, so I am wondering if you have carried out number 1 above.
Without knowing where you are, it isn't possible to work out whether this might be the case and which channel might be a good replacement.
I presume that the aerial feeds into the Sky box and then back out again to the other TVs. If there is a digital (Freeview) signal now on C44, this will cause interference on the analogue picture, as you might expect; it will appear grainy.
Try removing the incoming aerial lead to the Sky box. Then have the Sky box powered on and go to one of your TVs and attempt to tune in the analogue part. If there is manual tuning, then tune to C44. You may also look to see if the Sky box is still stored on the TV (in the analogue part), e.g. on number 6. Having got the output of the Sky box on the screen (via the RF feed), go back to the Sky box and plug the incoming aerial lead in. If plugging the lead in causes the picture to go grainy then you know that their is a digital signal coming down the aerial lead on C44 (or adjacent channels). If this is the case, then provide your location, preferably in the form of a post code or nearby post code (e.g. a shop) and we will see if we can work out what channel might be best for you to use.
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Alex D: I assume that you are picking up Moel y Parc, for which BBC is on C45 and ITV Wales/S4C is on C49.
Run the automatic tuning scan with the aerial lead unplugged up to C53 (if it gives channel numbers during the scan) or 66%. This should miss out Moel y Parc channels.
If you don't get it in in time, you may have to manually add Winter Hill channels:
C54 BBCB (HD, if applicable)
C55 ArqB (Yesterday etc)
C58 SDN/ITV3 etc
C59 D3&4 (ITV1 etc)
If you find that the thing decides to retune when unattended, then see if there is an option to stop it doing so. Indeed, as a matter of course it might be a good idea to disable such a "feature" as it would appear to be a nuisance. There isn't forced to be an option to disable it and if does turn out that it retunes at will, then cross that bridge when you get to it.
There are two possibilities that spring to mind:
1. An attenuator to reduce all signals with the hope that the Moel y Parc one is weaker and will, with sufficient attenuation, become so faint that the receiver doesn't use it.
2. A filter to only allow Group C/D channels through (C48 to C68). I'm not sure how effective this might be. Whilst it will reduce C48 a bit (owing to the fact that it's near its cut-off), ITV/S4C from Moel y Parc is on C49. It also uses C51 and C52 for two of the Commercial multiplexes, although they are lower power than the Public Service channels so may be less likely to be picked up.
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matt: All channels that were broadcasting before are broadcasting now. Without saying which are missing, how might we offer an explanation and a possible fix?
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Andrew Walter: The BBC channels from Dover on C50 are as they will be after 27th. That is, they have "switched". Obviously check that they are coming in on C50 and not another channel which would indicate that your receiver is tuned elsewhere which would therefore be the problem.
At under 3 miles from the 80kW transmitter your receiver could be being overwhelmed by the strength of the signal. Therefore this could get worse when all the other channels go up to full power.
You may need to get yourself an attenuator:
ukfree.tv - independent free digital TV advice
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Colin: Obviously try the "existing" aerial vertically. Indeed, whilst there is perhaps nothing lost to try it horizontally, be mindful that vertically is expected to be better.
Could you receive digital before switchover?
Did you have to wait until 18th April to receive the Commercial channels?
I'm not a professional aerial installer, but I use a loft aerial. It was sufficient to get solid reception on all channels before switchover.
However, after switchover I found that my Sony RDR-HXD870 froze for a few seconds every 15 or 30 minutes on the worst affected channels. With two other receivers connected to the same aerial as well, all tuned to the same channel, the others were solid and the Sony continued with occasional freezing.
I moved the aerial down the loft and replaced it and the problem continued. It was mounted on the L shaped bracket on one of the rafters.
The solution was to use a straight pole and mount it on the top of one of the joists so as to allow 2 or 3 feet between the back of the aerial and the sloping roof. Previously it was more like a foot with the L pole.
There is another loft aerial, which appears to be a shorter Philex SLx model to the one you have. This works solid even though it is also mounted with its rear within a foot of the rafters and felt. It has a massive reflector on the rear so I can only conclude that it screens against whatever the roof does to affect the signal.
Obviously different roof types affect the signal in different ways. Also the direction to the transmitter probably plays a part.
You might try sloping it upwards a bit, with the thinking that the signal is "sort of" coming from above.
I would be looking to test whether it may be too much signal. I tried this with my own problem and it didn't make a scrap of difference, although I'm 25 miles from the transmitter so it's not likely to be the cause.
Try connecting the lead to the TV with only the centre conductor connected. So strip back the screening and put the centre core into the centre of the TV's aerial socket. Then see what you get on C28. It's crude but it should hopefully "loose" some signal if this is your problem.
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Karen Furley: The rest of the channels come on 27th of this month.
That's the good news. There's two "buts"...
1. ...But "HD Ready" means that the set will not receive HD programmes over the air (via Freeview). I don't know whether you're aware of this as it catches a lot of people out (and which is probably why the marketeers like the phrase). All it means is that the TV can show HD pictures, but that they must come from another source, usually a set-top box.
2. ...But you may or may not be able to receive the full complement of Freeview channels.
The Public Service Broadcaster (PSB) channels are BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD channels. The rest are the Commercial (or "COM") broadcasters and they include ITV3, Pick TV, Yesterday, Film 4, Dave and many others.
If your aerial is directed to the Elham relay transmitter then you should be aware that it will carry only PSB channels. The aerial will be pointing north-easterly and will be vertical (elements up/down).
If your aerial is directed to the Dover transmitter, then you may be able to receive the COMs (it transmits PSBs and COMs). Dover is a little clockwise of east and your aerial will be horizontal.
The COMs cover 90% of the population whereas the PSBs cover about 98.5% of the population. The reason for the difference being that the COMs work on a profit-making basis selling advertising to show to viewers which they wish to aquire at lowest cost to themselves.
The COMs broadcast from the 81 largest (by viewer population) and achieve their 90% coverage. There are nearly 1,100 small "filler-in" transmitters like Elham and the cost for them to transmit from these is roughly equal to the amount it costs them for the 81 they have. When considered that the relays would only add 8.5% population to the potential viewer-base, it's not surprising that they're not interested.
The PSBs have a "Public Service" obligation, as the name implies, and the COMs don't.
The other main free-to-air service is Freesat and this may be particularly attractive for those not able to receive the Freeview COMs.
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Algernon Black: You haven't provided a link to the said page.
As a test, I entered the post code of The Sherborne Arms into the Digital UK Tradeview predictor:
Postcode Checker - Trade View
The retune in October of next year is because SDN is moving from C62 to C50. At this location the predictor considers the current channel "good" and the future channel "variable".
The predictor, as with any predictor, in no way suggests that anyone "will" or "will not" receive anything. It should merely be taken as a guide, being mindful that there are many many variables, not least that a post code is a massive space where signals vary and of course the fact that Royal Mail does not deliver television signals.
All I would suspect here is that C50 is used by another transmitter and that it has calculated that it may act to degrade reception. That does not mean that it will.
I wouldn't be concerned about what the predictor says; I would just be mindful of it. What matters is what actually happens.
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Simon Holland: Without knowing your location it is impossible have much of a chance of shedding light on the problem.
Not all transmitters carry all channels, Yesterday and other Commercial ones having restricted coverage. The fact that you picked it up one day and not another could be as a result of the fact that the transmitter that your aerial is directed to not broadcasting it.
What's your location, preferably in the form of post code or nearby post code (e.g. a shop)? What transmitter are you using or which direction does your aerial point if you do not know which transmitter it is directed to?
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Carol Golding: It is impossible to give a very specific answer as to what to try without knowledge of your location so as the likelihood of reception may be checked upon.
The thing that springs to mind here is that it would probably be better to extend the fixed roof-top aerial that you have (if you have one) to serve the "den" as well. This would irradicate any intermittant reception, as set-top aerials really aren't the best as they are in an environment where the signal isn't the best.
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Tony: HD is not broadcast from Bluebell Hill or Dover before switchover. Both these will complete switchover on 27th when their HD multiplexes will come on air.
Looking at the predictor, Rouncefall is roughly off the back of your aerial and its HD channel is C47, so you could try manually tuning to it until 27th. I don't have first-hand experience of HD receivers, but I understand that when manually tuning some, such as Humax, you have to specify DVB-T2 mode, which is that used by Freeview HD broadcasts. If you don't then it probably defaults to DVB-T which is what Freeview standard definition services use.
I suggest that you use the booster if it can be seen to be of benefit. With digital reception you need enough signal to be above the threshold for your TV to resolve a picture. Signal levels vary over time, e.g. due to the weather, so the signal level needs to be high enough above so that any drop won't put it below. Where this is the case, then the expected result is that reception (availability of channels) will be hit and miss.
The signals after switchover are stronger, so after 27th try removing your mast-head amp. You may also try Dover.
What you aerial is best suited to depends on its type. Bluebell Hill will be all Group B, except for ArqB which will be just outside, so a Group B aerial will probably work. Dover is C/D. Crystal Palace is Group A. If your aerial is a wideband then it will work for all, although wideband yagis aren't as sensitive on Group A channels. If you want to know more about this, see ATV's site www.aerialsandtv.com
In particular these may be of interest:
Aerials, TV Aerial and Digital Aerial
Gain (curves), Again
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
Bluebell Hill Transmitter
Crystal Palace Transmitter
Check that your receiver is tuned to the desired transmitter as sometimes they don't. There are six multiplexes after switchover and one service from each is: BBC One, ITV1, BBC One HD, ITV3, Pick TV and Yesterday. Check the signal strength screen to see that each are tuned to the correct UHF channels for your chosen transmitter.
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MF: Based on what I've seen on here, some viewers using Hastings transmitter may be affected by others co-channel and may have to change transmitter.
I'm not an aerial installer so the following are just my thoughts as technically-minded anorak on this subject.
If your aerial is a Group A one (bottom third of the band), then it will be unsuitable for Heathfield as it is now Group B (middle third of the band).
If you are looking at DIYing or just wish to be informed, then I recommend that you look at www.aerialsandtv.com
There is a page on Heathfield, although the recommendations still say it is C/D, which is what it was before switchover:
Heathfield Transmitter
You appear to have quite good line of sight (*with no local obstructions such as trees or buildings*):
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
The transmitter is 14 miles away. I looked on Streetview and St Mary's House and neighbouring tall building looks as though they could pose a problem. It may vary from house to house what can be picked up and what can't.
Dover looks out of the question.
The only other thing I can suggest is that you may be able to mount the aerial such that your house or some other object acts to block the signal from Eastbourne. This in so doing probably means putting the aerial somewhere where it is likely to pick up less signal from Hastings.
Mounted on one side of the house might help. Or in the loft where you can construct some sort of shield with chicken wire and tin foil. I've no idea how effective this might be, particularly as other buildings may reflect the Eastbourne signals back towards the front of your aerial (depending on which way you face).
The COM channels use a less robust mode (less error correction) than the PSBs and this is so that they can cram in more services, so they are going to be the first ones to go, even without the noise from Eastbourne.
It is worsened by the fact that they are both vertically polarised, although the stronger the signal the more it can be picked up by an aerial of opposite polarisation.
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Matt: The answer to your question depends on which transmitter that you are using.
Based on the fact that you have lost Dave and Viva as well, then I gather that you are receiving from Hastings transmitter. The reason is due to the local Eastbourne transmitter (which doesn't carry these services) using the same channels as these services from Hastings.
If it is possible to receive from Heathfield, then that is what you may have to do in order to receive the full complement of channels. Should you do this, then you should be aware that the SDN multiplex which carries ITV3, QVC and others is on low power until 27th, so you may not be able to pick it up until then.
As I said to MF, Hastings uses Group A channels (bottom third of the band) and Heathfield uses Group B ones (middle third), so if your aerial is a Group A one it will be unsuitable for Heathfield. A wideband one should be OK though, although the older the aerial, the more likely it is to be a Group A one.
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John Langley: C46 is now on full post-switchover power and the rest remain on their pre-switchover "low" power.
Based on the readings you have given, I am wondering if you live in a strong signal area, or at least your aerial is providing a very strong to excessive signal, the latter being a possibility for C46 now and for the rest when they go up on 27th. Without knowing your location, it isn't possible to get an idea of how likely that might be the problem.
What stands out to me is that for the high-power multiplex on C46 you only have a strength of 46, yet 24 and 39, which are still on low power, are in the 80s. With the low-power signals you have ample strength so I suspect that the low strength reading for C46 is because it is excessive and requires reducing.
42 and 45 are close to 46, so perhaps latter the high power signal is acting to desensitise your receiver when it is tuned to the formers.
This can be likened to walking down the street at night. When car headlights come towards you, your eyes become desensitised making it more difficult to see the relatively dark surroundings.
If you have a booster (and it is not used to split the signal to different rooms) remove it. Once you've done that, if the problem prevails, you may need attenuation to bring the level down even more.
You may find that as you reduce it, not only will the strength of C46 go up, but the quality of 42 and 45 will improve.
For a more in-depth explanation see ukfree.tv - independent free digital TV advice
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Andy: Retuning on or after 27th should be expected to restore these channels.
If your set has manual tuning, then manually tune to UHF channel 48 which is what these services are currently being broadcast on.
If you have a booster, then it is probably best removed. This may or may not help with your reception of COM5.
Once the booster is removed, if you got nothing tuning to C48, then try again.
Different sets work differently and have different sensitivities, so it might be worth trying each one (if they allow manual tuning).
As far as signal strength goes, it isn't so important; it is quality that matters. So the objective is NOT to get the strength bar as close to 100% as possible; indeed this could indicate too much signal strength.
For this reason I suggest removing the booster. So long as the quality is excellent, then the picture will be the best will ever be.
Different sets use different scales, so don't go comparing expecting like for like readings with the same aerial.
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Colin: Let us know how it goes.
I can see the contours on the map and from the satellite images they have trees on them which could be a problem. They may be a problem all the time or just at some times, such as when they're wet, blowing about or when they have leaves on. Or, having sorted the problem with C28, you may be lucky and never encounter poor reception.
Try to get C28 tuned in, even if this means taking the aerial and moving it, perhaps on the first floor or even outside in the garden. Each time, do a manual tune on C28. Logically, it would seem a good assumption that the further away from the bottom of the decline you are the more chance you are of picking it up. Try moving in that direction (going into the garden if necessary). Whilst moving it, try and view the strength and quality of the other multiplexes to get an idea of where the best and worst spots are.
The COMs (25, 22 and 28) use a less robust mode of signal, so a poorer signal makes them more susceptible to break-up than the PSBs (24 and 27). I have no idea to what degree that might affect things, but maybe being mindful of this might help identify "not-so-good-spots".
Different receivers have differing levels of functionality and usefulness for the DIY aerial installer. Some give little away, maybe having a single scale for both strength and quality. So look at the receivers you have and find the one or ones that give the most information and use it/them for your testing.
Once you have C28 tuned in and it has added the services on it (Yesterday etc), then don't retune as the tuning is correct.
Try to logically discount things. So if the cable runs down from the loft to the lounge and you keep going down to the lounge to look at the set, then disconnect the cable from the aerial and attach a short piece to which you connect a TV to see what you get.
If you then get something on C28, keep it connected like that whilst you site your aerial to best effect. Then turn your attention to the seemingly faulty downlead. Maybe try the old aerial as well and see which works best.
I should point out that if you have a distribution amp for feeding multiple rooms, then disconnect this whilst you're trying to get your aerial to work. It could be a problem caused by the amp.
If you have a mast-head amp, then trying with and without and with varying levels of amplification (if there is such a setting) might be worth a try.
Always be mindful that you could have too much signal and be looking to test the theory.
An aerial's gain in one direction comes about at the expense of sensitivity in other directions. So to have more gain, there is more loss of sensitivity in other directions. So a higher gain aerial tends to have a narrower angle of acceptance.
If you live within line of sight of the transmitter, but a long way away such that when the signal gets to you it is weak, then obviously gain on the narrow beam from the transmitter is what you want.
But the lower you live down a drop, the more you are trying to pick up a less focused signal. If the brow and the slope have trees on, then they will be moving about changing the signal. Thus an aerial with narrow acceptance angle may be what you don't want in such circumstances.
As I say, I'm not a professional but I've seen this explained and it makes sense.
I cannot say whether this is or is not of importance in your case. Clearly the fact that you are close to the transmitter helps more than if you had been further away.
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jo: You should attempt manual tuning.
BBC standard definition and radio = C50
ITV1, C4, C5 etc = C43
HD services (if applicable) = C40
For those you have, see that they are tuned to the above channels by viewing the signal strength screen.
A more specific idea of your location may help be more specific. For example, if you are close to the transmitter, your signal might be a bit high and in need of reduction.
Also, you "may" be able to receive from another transmitter that carries all the Freeview channels, albeit that you will probably need another aerial.
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John Langley: Due to the fact that the pre-switchover digital signals were weaker, some aerials have been replaced with higher gain ones. Plus the fact that with some transmitters, including Bluebell Hill, some pre-switchover digital channels were out of the native analogue group.
Bluebell Hill was Group E for four-channel analogue which covers the top two thirds of the band. All but two of the pre-switchover digital channels are in Group E, but two are below it (in the bottom third, aka Group A).
Sensitivities drop off gradually, but the fact that the weaker signals are out of group would have been likely to cause issues for some futher away. Wideband aerials may have been fitted so as to pick up the two Group A channels.
Oh, and there is no such thing as a "digital aerial" ! I presume you have a wideband aerial.
After 27th, all Bluebell's channels will be within Group E, with only one being outside of Group B (middle third) and at that it is only one channel outside, so Group Bs will probably work.
For an explanation of aerial groups, see Aerials, TV Aerial and Digital Aerial
-----
I digress.
What you don't know is if the overloading is occuring on the input of the distribution amplifier or the input to each TV or a bit of both.
If the signal on the input of the amp is too high for it to cope with, then it stands to reason that the outputs will be distorted. No amount of attenuation of the outputs will right the problem and no amount of reduction of amplification will right the problem.
So you need to go to square one and see what sort of level you have from the aerial by connecting directly to it.
You "may" find that there is that much signal that you replace the powered amp with a non-powered splitter.
If you still have your old aerial (the one that you replaced the current high gain one with), then that may be suitable. All channels are in group and the signal strength will be on a par with the former analogue that it used to pick up.
For more information on this subject, see www.aerialsandtv.com
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John Langley: You can pick attenuators up of sites like eBay. ATV also sell them.
I personally find that, since Maplin went onto the high street, its prices tend to be high and that the stuff it sells can be obtained for less from online sources.
It's good practice to use F-connectors for connections that are perminant (so to speak) such as in the loft. Use coax connectors for behind the TV set.
Some attenuators have coax connections, some have F-connectors.
To connect a TV directly to the aerial, connect the cable from it to one of the output feeds to one of the rooms. Bear in mind that there will be a certain amount of loss in that cable; that is the signal coming out of the cable into the TV will be lower than that coming out of the aerial cable (in the loft) and going into the feed to the room where the TV is.
You could take a TV into the loft and try it directly.
And/or reduce the level of amplification if it has a control on it. See if this rectifies the problem.
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Simon Holland: The situation with Heathfield is that COM4/SDN remains on low power until 27th.
For a full list of Freeview channels, see this page:
DMOL Post-DSO Multiplex Channel Allocations
It's those with a bullet in the "E" for England column that apply.
Which group(s) are you missing?
If you are missing COM4 and your receiver has manual tuning, then try tuning to UHF channel 48.
If you have a booster, then remove it. Try again tuning to C48.
If, having removed the booster, the other channels have good quality, then leave the booster out. Only if you find issues with weak signal and poor quality should you consider installing the booster, although it's not forced to fix it.
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Ian Foord: SDN is on low power until 27th.
BBCB should be available. Are you sure that your receiver has a DVB-T2 tuner in and not just a DVB-T one?
A "HD Ready" TV doesn't have the means to receive Freeview HD signals. "Full HD" does not mean that it can necessarily receive Freeview HD signals, it simply means that the resolution of the HD picture that it can display is the maximum resolution of 1080p.
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Terence: If you're looking at DIYing, see www.aerialsandtv.com for the products that the professionals install, as well as information to help you with the task.
You won't find a single aerial that will work with both because aerials are directional and polarised.
It might be a good idea to use double-screened cable, particularly for the Heathfield aerial due the older stuff having greater loss and reception not being good.
ATV has a page on Heathfield, although the recommendations are somewhat out of date now as it was previously Group C/D and now is Group B:
Heathfield Transmitter
In particular, see also:
Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads
Online TV Splitters, Amps & Diplexers sales
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julie: Bring up the signal strength screen whilst on BBC One and check that it is tuned to UHF channel 50 (706MHz).
If it is not, then say what it is and I may be able to suggest a workaround. You could confirm that other receivers are tuned to C50 for BBC One.
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Tony Lewis: I situations such as this it is very helpful to know your location and what transmitter you are using. If you don't know which transmitter, then a location and direction of the aerial should allow it to be deduced.
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Tony Ashby: Could you receive Freeview before switchover?
I am wondering whether your reception is marginal and therefore the COMs will be subject to being hit and miss.
What happens when you bring up the signal strength screen? Is Dave on the TV and what is the strength for it?
What is the strength for ITV3 and Yesterday as well?
ITV3, Dave and Yesterday are all carried on different multiplexes (different signals) and these are less robust and not as strong as BBC, ITV1 etc.
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Dave Gamble: COM4 (which carries Quest and ESPN among others) is on low power from Heathfield and will remain so until 27th when a retune will be required.
You may be able to use manual tuning (if available) to restore it. It is currently on UHF channel 48.
For a list of Freeview services, see here (it's those with a bullet in the "E" England column):
DMOL Post-DSO Multiplex Channel Allocations
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julie: If the screen says that it is tuned to C50, then it is tuned to Dover. If it gives another number, then it is tuned to another transmitter, perhaps one that has come on air at switchover.
If it is tuned to another transmitter, then it is not surprising that reception is poor.
However, if it is tuned to Dover, then what springs to mind here is that it is overloaded with signal. Too high a signal level manifests itself as too little signal, as far as indicated signal strength goes.
When the signal level goes higher than the receiver can manage, it starts to overwhelm the tuner and the indicated signal strength will go down. Fluctuating strength and poor quality may also ensue.
The reason I suggest this as a possibility is because you say that the low power pre-switchover signal is showing as high strength. If that's registering as "high", then the post-switchover will be higher still.
If this is the cause, then the solution may be to remove or reduce the level of the booster.
Is the purpose of the booster to distribute the signal to different rooms?
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julie: "If" the problem is too high a signal level, then that needs putting right; the answer isn't to buy a new TV. The other channels will be going onto full power in two weeks time so the problem could be compounded.
I had assumed that the aerial fed directly to the booster as that's where they should really be used. I got the impression that it was put in as part of the new aerial installation and therefore that all TVs were fed via it.
A better idea of your location (preferably postcode or nearby postcode such as that of a shop) may allow better prediction of expected signal level so as to get an idea of likelihood of too much signal.
Is this a high gain aerial?
The two leads from the aerial should be connected using a splitter. Two cables should not be put under the aerial's terminals as that's a bodge-it job and who know's what's happening if they are.
As for too much signal; you can get attenuators which you connect inline with the aerial lead to bring the level down.
Is this booster connected to one of the two leads from the aerial? I should imagine that it wants removing, certainly after 27th.
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julie: At 10 miles you could perhaps have too much signal. If the booster is on the end of one of the feeds from the aerial, then it will probably be surplus to requirements after 27th.
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Gary: What's the model number of the Tosh? Some older models weren't built to the full DVB-T spec and won't receive signals that are in 8k mode which is what's used after switchover. 2k mode is used before, which is why non-BBC channels are still available.
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Malcolm Wood: Looking at those trees on the slope, I suppose that rules out Heathfield. Maybe you have already been along this road...
There seem to be quite a few houses on Sandcroft Road receiving from Dover. The problem there is that the COMs are half power to the PSBs, plus the COMs use a less robust signal mode (less error correction).
I suppose that you had a wideband aerial installed for Hastings so as to receive digital TV (because two were out of group). I sympathise as it looks as though you are going to have to change it again (if indeed there is a possible solution) or Freesat may be your only option for additional free-to-air programmes.
I'm not an aerial installer, so I wouldn't like to gauge as to your chances of success.
However, yagi wideband aerials' gain levels are lower at Group A channels, of which Hastings uses exclusively now. See for examples:
Gain (curves), Again
Your aerial is stuck up above the roof-line, and you're probably going to tell me "it needs to be". You're also higher than others which is a pity.
As I say, I'm not sure of the likelihood of success, but in situations such as this, the only thing to think about is is there somewhere where the aerial could be mounted where it will get sufficient signal from the desired transmitter and where it will be shielded from the interferer?
Even if there is somewhere suitable, the spanner in the works may be objects around you reflecting the interfering signal towards your aerial, if it is strong enough.
Assuming that you have no local obstructions, then this plot suggests that you can see the top of the transmitter mast:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
The only possible fly in the ointment to mounting the aerial lower that I can see are the trees around the edge of the recreation ground behind you.
But if you can get line of sight, then that is good for a high-gain aerial, as it can be pointed at the beam. The higher the gain of an aerial, the smaller the acceptance angle is (although obviously they all pick up from all angles to varying degrees).
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Malcolm Wood: See Digital TV Transmitters and other parts of the ATV site for information.
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julie: What you have described - the penny has just dropped!
The booster is probably on the roof as you say that the thing that has the adjuster is on the roof.
I suspect that what you are describing as the booster (the one behind the other TV) is in fact the power supply for the booster (on the roof) and not a booster itself. Try turning off the power to what you believe to be the booster. If it is in fact the power supply for the booster on the roof, then I would expect all signal to be lost, including on the Matsui as a booster with no power going into it won't have any signal coming out of it.
Therefore the two leads are connected to the booster on the roof.
I think that you need to get the installer to look at it. If there is too much signal, which there could be, then he will know what to do.
As for why one works when the other doesn't - different sets have different tolerances.
You're going about this the wrong way, if I may say so. If the signal is excessive, which judging by the power increase (before vs after) from Dover, it could be, then that needs fixing. Trying to find a television that will tolerate excessive signal is not the answer.
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Gordon Ormston: Confirm that it is tuned to C50.
If that doesn't fix it, then I would suspect that the signal level being fed into it is now too high and is in need of attenuation.
See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Gordon Ormston: The high power post-switchover signals are such so as to provide equivalent coverage to that of the former analogue (at least for BBC, ITV1, C4, C5 and other Public Service channels).
Due to fewer frequencies being available, transmission powers had to be kept down so that they could be re-used by transmitters within a closer proximity than they otherwise would have been. Also, power was low so as not to interfere with analogue transmissions already on air which were co-channel.
In essence, it was a quasi-national network; i.e. there were gaps in coverage which is why we have a "switchover" and not just a "switch-off" (of analogue).
I assume that they covered as much of the population as they could with this network giving greater preference to those transmitters with more viewers (the assumed objective being to cover as many as possible). In any case, international clearance would have had to be granted with any signals along the coast being more likely to affect the continent.
So there was probably little that could be done if the pre-switchover service was to be crammed in.
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See ukfree.tv - independent free digital TV advice
A variable attenuator such as that shown on that page will cost £3 or £4 from online sources such as eBay. These are usually 20dB ones.
As an example (others are available!) I found this one:
VARIABLE ATTENUATOR TV SIGNAL REDUCER 20dB 3 5 6 9 10 12 15 18 DIGITAL FREEVIEW | eBay
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julie: I wish you well in getting it sorted.
I'm sure that the problem will be easily rectifiable by the installer.
Tell your mum not to worry. Her TV viewing will continue thanks to your efforts and she is lucky to have such a caring daughter.
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Andrew Walter: There is always the possibility that you need even more attenuation than you have. Perhaps connecting two attenuators inline with one another, one of them being a variable one.
The mast head amp needs removing, no doubt. With it in installed, its the signal from the aerial could be too high for the amp to cope with. Thus the signal will distort at the amp.
So the output of the amp will always be distorted. Adding attenuation will therefore give you a smaller distorted signal.
To pick-up less signal, whilst tuned to C50, try a 12 to 18 inch piece of wire inserted into the inner part of the aerial socket. Or use a set-top aerial. Or, as a crude attenuator, try your roof top aerial with a section of the screening removed so as to "loose" some signal.
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Debby: See my posting immediately before yours which answers your question.
ITV3, 5* and 5USA are all carried on COM4 multiplex.
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Trish Stygle: The Chartham transmitter currently carries only BBC services, which is what happens at the first stage of switchover.
At the second and final stage on 27th, the rest come on air. Until then, ITV and Channel 4 continue to be available in analogue, as does BBC One.
The bad news is that Chartham will only carry Public Service channels which are BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services. Furthermore, aerials installed for Chartham which are Group A ones will be expected to work fine for digital and therefore a wideband aerial is unnecessary.
To get more channels, you will have to investigate how likely you might be able to receive from another transmitter that carries them, such as Dover.
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kaz: As I you've gathered, SDN is shown above to be on C42+ which is incorrect as it is on C48 now and will go to C42 on 27th. Until then, it is doubtful whether you will be able to pick it up.
Perhaps the Sky box puts a signal out on or near C44 which is preventing reception of it on the TV. In order to discount this possibility, connect the incoming aerial lead directly to the TV (or set-top box receiver if that's what it is). Then try again. If you successfully tune in C44 and then you loose it once you've connected the aerial lead via the Sky box again, then suspicion must turn to that.
If there is a booster (before the TV), then try removing it and then try again manually tuning to C44.
D3+4 being tuned to Bexhill really needs fixing because receiving from a direction other than to which the aerial is pointing could leave the viewer liable to poor reception at some or all the time.
Removal of any booster will reduce signal levels and therefore may make it less likely to tune to Bexhill in error.
Failing that, if the set has manual tuning, then you can run the automatic tuning scan with the aerial unplugged for part of the scan to miss out Bexhill. As this will also miss out some of Heathfield, you can use manual tuning to add them.
Try plugging the aerial in at 53%. You will probably pick up BBCA and possibly D3+4 and you will have to add the rest.
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Lesley: There is the possibility at switchover that "may" mean that you have to adjust the output of your Sky box, this being that a digital signal may have come on air on the same frequency you are using for your Sky box. This, as I say, is a possibility but you should go step by step.
If you have carried out an automatic tuning on the analogue side of the TV, the Sky box may have been put under number 1 if that is the only analogue signal to be found, as well it might. I would just leave it under analogue number 1.
Failing that, unplug the incoming aerial lead to the Sky box and then try again with tuning the TV. Then plug the aerial lead back into the Sky box. Then go back to the TV and see what the picture from the Sky box looks like. If it is snowy, then you know that there is a new digital signal coming down your aerial lead on the same frequency and you will have to change it using the instructions above.
Knowledge of your location (preferably by post code or nearby post code, such as a shop) will be helpful in working out a new channel to use, should you find that it is interfered with by a digital signal.
Obviously always ensure that the Sky box is powered on and not in standby so that it is putting out an analogue signal.
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Keith Myers: Without knowing your location my answer is more speculation than it may have been had I known your location.
Firstly, ensure that BBC One is tuned to Heathfield which is on UHF channel 52 by looking on the signal strength screen.
But there is a possibility that the signal after switchover is too strong, with this manifesting itself as being too weak and/or too poor quality a signal.
See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
In general terms, the closer to the transmitter that you are, the more this could be the case. A booster in particular could be increasing the signal too much.
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Malcolm Wood: The wonders of modern technology!
I hope you get it sorted.
Maybe the guys at ATV could advise you as to what might be your best choice aerial and any tips.
I did a plot using Megalithia with Eastbour South Tower and your location:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Click the link below the plot to view a map of the line between the two points. Unfortunately the houses on your road appear not to screen the unwanted signal.
Obviously as you're on a slight inline it makes it a bit more rough. But it does suggest that you are a little above the height of the broadcast antennas.
There is a tenth to two tenths of a mile before the ground drops for which there appears to be clear line of sight beyond and up to the Eastbourne transmitter.
So you are relying on the clutter on that tenth to two tenths of a mile to block the unwanted signal.
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Veronica Wells: If you are using a set-top aerial in your bedroom, then by their nature they can be hit and miss.
Take the set downstairs so as to connect it to the fixed aerial for the purpose of tuning it. Then, having tuned it, take it back upstairs and move the aerial to best effect.
If having taken it downstairs, and it still puts ITV3 on logical channel number (LCN) 3, then this sometimes happens where a receiver is not set for UK. Even if ITV1 is not picked up, ITV3 should still assume LCN 10 if the country setting is correct.
For the frequency/UHF channel number for ITV1, whilst on that channel, bring up the signal strength screen on the downstairs TV to see what it is tuned to.
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Peter: Maybe there is a disused roof-top aerial on Heathfield whose cable runs down the building and for which you could route into the loft and feed into the distribution amp.
As I say, I'm not a professional, but I understand that there are certain regulations with regards aerial systems that serve multiple dwellings. I understand these require appropriate earthing as well as electrical isolation between the outlets. I can't be any more specific than that.
I urge due caution; obviously I'm not saying that a particular aerial "will" work.
I did this plot using Megalithia, assuming your aerial to be 18m of the ground:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
As you can see, it would appear that you probably have line of sight (or near so). Only mile closest to you could have an obstruction on it as it is an incline.
For this reason, I wonder if a XB10B may be suitable:
ATV`s Choice Of Aerials for digital TV
The distribution amp will allow you to fine tune.
The higher the gain, the narrower the acceptance angle.
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David: The two main factors that increase the likelihood are:
1. Proximity - the closer you are, the stronger the signal that is in the air. (Obviously the more off line of sight you are, the less likely that you are going to get too much signal, e.g. if you are in a valley but not very far from the transmitter).
2. People who upgraded their aerials because there old ones weren't sufficiently sensitive to pick up the low power pre-switchover signals may find that their aerials are now too sensitive. These would "tend" to be further away than those who aerials were sensitive enough.
Again, distance isn't everything. People can live close but with obstructions and without line of sight.
The point is that the difference between the pre-switchover digital and post switchover digital is big.
Digital reception is about thresholds. So you need enough level of signal to get a picture (the lower threshold) and not too much as to exceed the upper threshold.
Those who, before switchover, had sufficient signal level (to be above the lower threshold), but which was below the upper threshold by an amount greater than the increase in strength (before vs after) will therefore be OK.
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albert: May I ask you what the make and model number of your receiver is? There are some that have known issues that will prevent them from receiving this channel from Hastings transmitter.
If it turns out that you have an affected device, then I'll explain what the problem is.
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matty: Heathfield C47 is BBCB which carries the four HD services (including those of ITV1 and Channel 4), therefore non-HD tuners will be unable to receive it.
A "HD Ready" TV means that it will show HD pictures, but does not have the means to receive them over the air.
"Full HD" means that the TV has a HD resolution of 1080p. Its presence adds no qualification to reception of HD signals over the air.
Where a set has a "Freeview HD" logo on and has DVB-T2 in its specifications, then it will be able to receive C47. Standard definition broadcasts use DVB-T, so if in the spec it only says this, then it won't pick up HD.
C42 shown above is incorrect and I've posted a message to the site owner so it may be corrected. COM4/SDN remains on C48 at low power until 27th June when there will be a retune.
If there is a booster, then it may be able to be removed. It may or may not allow reception of COM4 on C48, you may have to wait until 27th when it will be on C42.
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John Baillie: Click the words "HD Ready" for an explanation.
You've probably bought them thinking that they were "ready" to receive HD when it comes on air. What it means is that they can display HD pictures but don't have the means to receive HD signals off the air.
A separate HD tuner box will be needed for each one I'm afraid.
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KennyT: Err no.
Freeview signals are broadcast by terrestrial transmitters. A satellite dish picks up signals from a satellite.
You haven't given your location so it's not possible to gauge how likely it might be that this is the case, but if you're very close to the terrestrial transmitter, perhaps the lead from the satellite dish is picking up sufficient signal from it due to the signal being that strong.
This could also explain why you have poor reception on your communal terrestrial aerial system. It could be amplifying it too much. If this is the case, then it is the responsibility of whoever maintains the aerial system to put it right. It will probably affect others so you might ask your neighbours.
I emphasise that I make this suggestion on the basis that you "may" live close to a transmitter. Without knowing your location I cannot have any idea whether this is likely or not at all likely.
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stuart smith: Whereabouts are you in Haywards Heath?
Did you have Freeview reception before switchover? If so, did you get all the channels? If you were missing channels, which ones?
Did you have your aerial replaced with a wideband aerial?
Are you using a communal aerial system such as in a block of flats?
Heathfield formerly used C/D channels (top third of the band) for analogue. C41 is the lowest which makes it Group B (middle third). Consequently some C/D aerials may not function too well whilst others will. If you have a C/D aerial in a poor reception area, then it might need to be replaced.
Contract aerials are the cheapest and C/Ds can have poor gain below their intended frequencies.
If you answer the above questions it might help to home in on whether this is the problem.
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Ian Foord: I put the post code BN22 0EP into the BBC Reception website (www.bbc.co.uk/reception) and selected the options to say I had a problem with reception of Freeview TV.
Understandably there are notifications about the DSO in the early hours of Wednesday.
However, Hastings shows "from 16:19 on 13 Jun". Heathfield reports "No problems".
So whether it is off-air or not, BBC Reception doesn't seem to say.
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Mike Hall: This site is an independent one and not connected to any of the companies involved in broadcasting.
Bilsdale is undergoing engineering works in preparation for switchover. See the note at the top of the page.
I've never understood why Yorkies would want to watch Tyne Tees, unless they couldn't receive Yorkshire of course. I know that Bilsdale comes in strong, particularly in the north of the city, but why watch news about the north east if you don't have to?
As a fellow Yorkshireman, I want to hear about what's going on in God's Own County!
I reckon that you're on a communal aerial, so tell your landlord that the aerial needs turning to face Emley Moor!
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Alison: Can you post the make and model of your receiver? Some older models won't work after switchover.
BBC signals have now "switched", and therefore affected models will loose the ability to receive BBC channels. The model number will help determine whether this is the case here or not.
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Kathie: Yesterday, ITV4 etc from Dover is currently on C55, so if your set has manual tuning, try tuning to it.
If you can't get it, it could be that previously you were "only just" able to receive it due to its weak strength. The strong BBC signal may have had an adverse effect on reception of other channels. This should correct itself when you retune on 27th.
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Ian Foord: Sorry, that should that BBC Reception reports for Hastings: "HD Digital TV Off Air from 16:19 on 13 Jun".
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Rob: If you receive your TV from Waltham-on-the-Wolds then have you had your aerial replaced? You may have had it replaced to receive digital TV before the switchover which happened last August.
If your aerial is pointing at Waltham, then bring up the signal strength screen whilst tuned to Quest and check that it is tuned to UHF channel 29.
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Mike Gordon: I don't think that the problem could be too high a signal strength (which can be rectified by attenuation).
The tall aerial masts can clearly be seen on the Bird's Eye photographs on Bing Maps and these tell a story.
The problem would appear to be that you live low down and that you are receiving the signal over the brow of a hill, and are close to the hill at that. The problem of the signal going at night is probably caused by the vegetation on the hill or slope getting damp and acting to reflect the signal away.
To understand this, imagine that the signal was a large beam of light. Due to the fact that you're over the brow of the hill of don't have line of sight, you're trying to pick up when light comes over the hill.
Now consider when the sun is low to the ground and shining through trees. The trees cause shadows and as the wind blows, the light changes. Now apply this understanding to what's happening to the signal to your property.
I have set out below an analysis that shows there are a number of groups of trees that are likely to be problematic.
You probably saw the effects with analogue. I expect that when it was wet and windy it be particularly bad as not only would the trees be acting to reflect the signal away because they're wet, but the bits of signal that get through would be changing owing to the fact that the trees were blowing about. Maybe it was different to differing degrees at different times of year, the signal getting better when the leaves fall of the trees.
I did this plot of the signal path from Crystal Palace to your house:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Click the link below the plot on that page to view a map of the area between the two points.
I zoomed out so that both points were visible on the screen. Holding a ruler up to the screen I found that the length of line to be 22cm. The distance to the transmitter is 22.1 miles, so I then looked at what's on the ground in the first mile and a half away from your property. This is the red bit marked on the plot and appears to be roughly up to Breakspear House or thereabouts.
The trees at Old Orchard Lodge would appear to be in the way and quite close at that. The signal path intersects Church Hill, somewhere near Countess Close. Assuming that it is close to the ground, you have the buildings there as well. The trees your side of Dovedale Close, near Chestnut Cottage look as though they could just be in the way. The line doesn't quite intersect them, but the point at your end isn't quite on your house. Then there are trees near Breakspear House as well, which is about a mile and a half away, so I think that's your lot.
Everything further away from you would appear to be under the line of the signal. That is, Bayhurst Wood Country Park, for example, is in a dip and therefore the signal goes over the top of it.
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The Commercial multiplexes, which include ITV3, Pick TV, Yesterday, Sky News and others use a signal mode that is more susceptible to break-up with poor signal than the Public Service ones (which carry BBC, ITV1, ITV2, C4, C5 etc.
The reason the Commercials do this is so as to fit more services in. This obviously comes at the expense of some fringe viewers.
Different receivers having differing levels of sensitivity and tolerances. This probably explains why some work OK and some faulter.
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Corin: I've pointed this one out before.
The reason it appears like this is because ITV3 is carried on PSB2 on the Channel Islands owing to the fact that there is no +1 version of ITV1 Channel Television and that the transmitters there are PSB-only.
So it would appear to be a bug. The heading at the top of this page does say "ITV3 (CI)" which is different to "ITV3" as far as this site is concerned.
Briantist, can you do something to stop ITV3 from appearing on the comparison page in this way?
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Floyd: I can only be very general without knowing a location and which transmitter you are using.
If you're receiving from Sandy Heath, then many others have reported issues via this site in different places.
We know that there are due to be changes on or after 27th June that should improve the signal, so see how it goes.
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Malcolm Wood: I'm not sure how effective that might be or whether it may have an adverse effect on the sensitivity and directivity of your aerial. I'm not an RF engineer, so I can only but wonder:
- The interferer is at 90 degrees to the desired signal. Will putting foil on one side somehow unbalance the aerial and affect its directivity/sensitivity properties?
- The closer you put the foil to the aerial, the more affect it will have on it.
- The further away from the aerial you put the foil, the more the interfering signal will "get around" it and hence the larger the piece of foil will need to be to achieve the same effect.
In any case, choose whether you mount the aerial in the loft or on the back of the house, you may find that in certain weather conditions that reception isn't as good. I'm thinking that it's not so much that reception from Hastings might reduce in quality (although perhaps it might), but maybe the interfering signal might degrade reception more at times.
As I say, I'm not an expert in RF, so these are just my own musings. Perhaps one of the pros could chip in with some suggestions for Malcolm.
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MF: I'm not sure what is to be gained by complaining.
There are other places where similar effects have manifested themselves after switchover. Local relays usually degrade or make impossible the reception of the COM channels for those who do not use the relays (as the relays don't carry the COMs).
I imagine that it's been done in such a way as to minimise the number of people who end up loosing channels that they could get before.
There is also the fact that channels 31 to 37 and 61 to 68 have, or will soon be cleared. The former were or are to be auctioned for more Commercial multiplexes and the latter sold off to 4G mobile operators.
So the reduction in the number of available channels has played its part in creating situations where transmitters are co-channel in closer proximities where in days of old they would never have been.
It's the way things are done these days. The COMs do not have the extensive coverage that the PSBs do. All that's happened is a few people have lost access to them or have had it made difficult.
Others on here have reported this problem with Hastings' COMs being wiped out by Eastbourne and have said that they will have to look at changing to Heathfield. Unfortunately Malcolm isn't in a position to do likewise.
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Dave H: The fact that you can get QVC but that others are poor suggests that the signal being fed into your TV is too high and overwhelming the tuner.
For a list of services and multiplexes, see here (those with a bullet in the "E" England column):
DMOL Post-DSO Multiplex Channel Allocations
COM4 remains on low power until 27th June when there will be another retune. All the rest are up to their final power.
The booster should be removed from the roof-top aerial. If an aerial with line of sight for 22 miles to a transmitter at 20kW won't feed a single TV without any amplification, then there's something wrong. I suggest that it is unnecessary to have such a setup now.
If the booster connected to the loft aerial also acts as a splitter (it has two outputs), then it probably needs turning down. You may find that it can be removed and replaced with an unpowered splitter. Indeed, you "may" even be able to run all three from the same aerial with an unpowered splitter.
See ukfree.tv - independent free digital TV advice
See the website of Aerials and TV in Sheffield for lots of information as well as an online shop:
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
If you choose to run all off one aerial, then you could leave the other as a reserve. If the cable from the roof-top aerial were to run into the loft, then you could easily swap them (the feed to the main TV would obviously need routing from the loft).
It's best to use threaded F-connectors where connections are generally perminant, such as in lofts, instead of using coax plugs.
With F-connectors you can then swap aerials using a small spanner (although you could use coax connectors if that's what's on your distribution amp).
Obviously you may find that having completed these changes, you are unable to receive COM4.
Digital reception signal strength is about getting somewhere between upper and lower thresholds. So long as you are above the lower threshold for a receiver to resolve a picture, then the picture will be as good as it will ever be, providing that quality is excellent. If you go above the upper threshold then you are potentially overloading your tuner with too much signal.
This is why I say that the booster on the roof-top aerial can be removed as doing so wouldn't impact on the picture, unless it put it below the lower threshold, and as I say, at 22 miles if it does then there's something wrong.
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Dave H: One further thing. It's always worth checking that a receiver has tuned to the desired transmitter and that you aren't looking at the output of another transmitter.
For Heathfield they are:
PSB1=C52
PSB2=C49
PSB3=C47 (HD mux)
COM4=C48 (to move to C42 on 27th June)
COM5=C44
COM6=C41
The information at the top of this page which says that COM4 is now on C42+ at 20kW is incorrect.
Check the signal strength screen whilst on one service on each of these multiplexes. The first one on each are BBC One, ITV1, BBC One HD, ITV3, Pick TV and Yesterday. (Refer to the DMOL page of multiplexes I gave you.).
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John: The short answer is shortage of channels (frequencies). And the fact that the Commercial services' coverage isn't as extensive as the Public Service ones.
To understand the long answer, it is necessary to explain that there are two types of services:
- Public Service Broadcaster (PSB) | These being BBC, Channel 3 (the various ITV1 regions in England), Channel 4 and Channel 5. The PSB multiplexes (signals) also carry ITV1+1, ITV2, Channel 4+1, E4, More 4 and the four HD services.
- Commercial (COM) | These carry other services like ITV3, Pick TV, Yesterday, Film 4 and Dave.
For a full list of what's carried on what, see DMOL Post-DSO Multiplex Channel Allocations
This page shows that there are three PSB multiplexes and three COMs. Each is carried on a single UHF channel; each single analogue service used one UHF channel.
The design of the network of transmitters means that PSBs are given the same coverage as the former four-channel analogue. The plan was for aerials that worked with analogue before to work for the PSBs.
There are 81 main and larger relay transmitters that carry all six multiplexes. The 1,000 or so other small relays are PSB-only. The COMs achieve about 90% coverage of the population, whereas the PSBs cover 98.5%.
The COMs don't have a "Public Service" obligation which is why they don't have the extensive coverage that the PSBs do. So no one who can receive the PSBs is "guaranteed" to receive the COMs.
In some cases, aerials may need to be replaced to receive COMs. Or in the case of Rowridge viewers, they may need to adjust their aerials to vertical.
The horizontal signals from Rowridge are therefore primarily to ensure compatibility with horizontal aerials.
Due to the shortage of channels (frequencies) available, Rowridge's COMs use channels that are also used by other transmitters, including Crystal Palace and Stockland Hill (PSBs are not co-channel). These two transmitters are exclusively horizontal. Stockland's COMs are co-channel with those of Rowridge, but lower power to its PSBs. So you can see that they have had to restrict the coverage of Stockland's COMs so as to prevent interference. Or to look at it another way, channels are reused by transmitters in much closer proximity that they would have been previously.
So fringe viewers on Stockland, for example, will only COMs intermittantly, or may have to spend money on a more sensitive aerial, or may only be able to receive PSBs.
For the reason of these other horizontally polarised transmitters using the same channels, Rowridge's COMs have restricted power horizontally. That is, to protect against interference where Stockland and Crystal Palace overlap Rowridge.
The PSBs get the better channel allocations whereas COMs may get ones where they are restricted in coverage and in places where other transmitters prevent reception because they are co-channel.
Previously with analogue, each transmitter had four channels. With digital, the 81 most powerful transmitter require six. Plus there is the fact that the number of channels available is reduced due to the plan to sell of some for 4G mobile operators and some more being ringfenced for selling to three more COM licencees. If the channels set aside for future COMs had been used, then there would have been less clashes and less people who have to replace or adjust their aerials.
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stuart smith: Communal aerial systems are sometimes filtered to only allow channels that are used through (or only allow group(s) of channels through).
Look at the table above, under the heading "Transmission frequencies". Accepting that there is an error which says that SDN is currently on 42+ when it is on 48. On 27th it will move to C42.
You will note that prior to switchover, with the exception of 29 and 34, the lowest channel was 47.
A filter that cuts off at one channel won't have an absolute cut-off where one channel gets through unscathed and the other gets attenuated completely. It may reduce a neighbouring channel a bit. So perhaps up to C39 or C40 is filtered which is why 41 is not good.
You "may" see some affect on 42 when it comes on air, if it is the aerial system that is the cause of the problem, and if it hasn't been rectified by then.
You need to establish, as firmly as you can, that the problem lies with the aerial system and not your equipment. If you have more than one TV or box, then try each in turn. When trying the TV, connect the aerial lead from the wall directly to the TV and not via a box, so as to discount the box as being the source of the problem.
On each receiver, assess the signal strength of each multiplex and compare, perhaps writing each down. Different receivers have different scales and tolerances, so don't compare a single multiplex between receivers; only compare all multiplexes on each receiver. See if 41 is down relative to the other muxes with all receivers. Obviously 48 is expected to be lower then the others.
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toniswift: No, only Absolute is available on Freeview.
See DMOL Post-DSO Multiplex Channel Allocations
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Peter: If manufacturers started using F-connectors, apart from the fact that adapters would often be needed, people would go connecting satellite dishes to terrestrial receivers.
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Stuart: See the explanation of my experience with a loft aerial:
ukfree.tv - independent free digital TV advice
I believe that I have line of sight, or near line of sight, from the roof whereas you clearly don't.
A cause of poor quality at night could be caused by dampness forming on trees which the signal path passes through. Or of course, it could be damp forming on the roof which is affecting the signal quality.
I used Megalithia to plot the path from your location to Hannington:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
As you can see, in the direction of the transmitter the ground goes up about a mile away and you are therefore receiving from over the brow of a hill.
Click the link below that trace to see a map of the area, complete with a line joining you and the transmitter.
I zoomed out until the two points were on the screen. I then placed a ruler up to the screen and found the line to be able 21cm long. The distance to the transmitter is about 21 miles. This allowed me to work out where the brow of the hill is.
It is around Ferhill Road, near Hawley Park and around which there are trees...
The flat bit coloured red that you see on the plot is Hawley Hill which also has woodland on it.
I think that you need to have your aerial mounted outside, preferably above the roof level.
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Stuart: I wrote the bit pointing you to my experience with a loft aerial before looking at the problem with the trees.
On the basis that you say that it is worse during darkness, I am of the opinion that it is far more likely to the trees. However, that doesn't stop you experimenting if it is possible to increase the gap between the inside of the roof and the back and front of the aerial.
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stuart: It's not surprising that you couldn't pick up any digital TV from Hannington before switchover because it was severly reduced in strength in your direction due to the fact that Guildford used the same channels.
If you have a seventies aerial on Hannington, then you should definately try it now. Indeed, I see on Streetview that quite a few houses have an aerial on each transmitter.
If you have a Crystal Palace aerial and you haven't tried it since it switched to digital in April, then you should try that as well.
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Keith Myres: If I am right in suspecting that you are served by a communal aerial, then I suggest that the problem might be that its amplifier needs turning down because it is boosting the signal too much.
This could be the case because the signal going into the aerial is now stronger than it was and hence the signal coming out from the outputs must be so as well. This could be above the level that receivers are built to accept and therefore the cause of your problem.
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Tom Murphy: This is an independent site. Information provided on it comes from official sources. Because the sources don't notify the site when there is a change or update to the engineering work, it is up to the site to "look". I have no idea how often it does this, but it stands to reason that there could be a delay in the information getting onto this site. This is why, at the top of the page where it says that BBC and Digital UK report no faults, that there is a link to recheck. Clicking the link will cause the site to "look" at the source information. The link is not present where there is an engineering works report shown.
You can view the source information yourself by going to:
- Digital UK | www.digitaluk.co.uk/engineeringworks
- BBC | www.bbc.co.uk/reception and entering your postcode and selecting the appropriate options
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Derek: Yes. The strength of the Commercial channels will (finally) increase. This will happen in the early hours of 2th when you will need to do a full retune.
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stuart smith: This suggests that it is a problem with the aerial system and that it needs adjustment following switchover.
It may be helpful if you can find any neighbours with the same problem.
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Gordon Ormston: What sort of reception do you get on the three remaining analogue channels? (56, 66, 53)
Try with and without attenuation.
Some other things to try are:
- a 12 to 18 inch piece of wire inserted into the inner part of the aerial socket.
- a set-top aerial.
- connect the inner part of the aerial socket to the lead from your aerial leaving a gap unscreened so as to "loose" some signal.
The transmitter is only 3 miles away and you're not far of having line of sight.
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Denise Hunter: ITV3 and others on SDN from Heathfield remain on low power until 27th June when a retune will be required. On that date the signal will go up to full power.
If you have a booster, remove it. It may or may not restore availability of ITV3. If it does not, but the other channels remain OK, then leave it out.
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Peter Richards: Perhaps you will have to wait until 27th June when ITV and others will go to full power. Only the BBC is on full post-DSO power now.
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Declan: What is sufficient depends on the location. Loft aerials get less signal due to it having to pass through the roof. Some roof slate isn't particularly conducive to a loft aerial.
See this plot which would suggest that you may have good line of sight at 14.5 miles:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Obviously this doesn't take local obstructions into account, which is why I say "may have". If you're in a house, then that's obviously better because the aerial is higher up than a bungalow. If you're in a bungalow, then it might be best to mount it on a pole so that it's above the roof line.
You may be able to conduct some tests in your loft with your former roof aerial, if it is still in one piece.
See ATV Sheffield's website for lots of information and an online shop www.aerialsandtv.com
See:
Aerials, TV Aerial and Digital Aerial
It does hinge on how much your roof will attenuate the signal, but it does look like a log might work in your location.
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Richard Hawkins: Perhaps it could be too much signal being fed into your receiver.
Tunbridge Wells and Heathfield are a "Single Frequency Network" (SFN) which means that they transmit on the same channels. This is perfectly OK as the digital system allows it.
Heathfield is horizontally polarised and Tunbridge Wells is vertically polarised, but your aerial could still be picking up Heathfield to a degree. What you get down your aerial lead is the sum of what's been picked up of the two signals.
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Keith: 626MHz is C40 which is from Sutton Coldfield.
What I suggest you do is run the automatic tuning scan and unplug the aerial when it gets to 30%. This will have the aerial in for Ridge Hill and unplugged for all of Sutton Coldfield's channels.
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Tony: This is the two-tier terrestrial television transmitter network we now have, I'm afraid.
Newhaven only carries the Public Service Broadcaster (PSB) multiplexes (groups of services).
Those that it doesn't broadcast are the Commercial (COM) multiplexes and these carry the likes of ITV3, Pick TV, Yesterday, Film 4 and Dave.
The COMs broadcast from 81 of the largest transmitters (largest by viewer population) and cover about 90% of the population. The other 1,000 or so relays, including Newhaven, are PSB-only. The cost to the COMs of including the relays in their portfolio would roughly double their cost of transmission whilst only adding about 8.5% of the population to their potential viewer-base.
As they are run entirely as profit-making ventures and have no "Public Service" obligation, they decided to turn down the offer of additional coverage.
In some cases reception of COMs can be achieved from a station that carries them. Obviously this requires a new aerial and in some cases due to poor signal, a big aerial and sometimes big mast.
Failing that, the main option to get more channels is Freesat. There are some channels like Yesterday and Dave that are on full Freeview (COM) but not Freesat.
I'm sorry it's not what you were hoping for. It's a common question and I believe that "Freeview Lite" has got to be the biggest let-down, particularly as mention of this inferior service doesn't feature in any of advertising. "Subject to coverage" fails to make clear that not all channels are available in all areas.
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Mazbar: Follow the link to DUK Tradeview or hover your mouse over the links on the right of Tracy's posting to see her post code displayed in the status bar at the bottom of your screen.
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Tom: The problems are in receiving the Commercial (COM) channels. These have limited coverage with respect to the Public Service Broadcaster (PSB) channels.
If you received four-channel analogue before, then you should get at least the PSBs now.
See here for a list (those with bullets in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
The PSBs therefore have BBC, ITV1, ITV1+1, Channel 4, Channel 4+1 and Channel 5, among others.
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Tom: It mainly depends on which transmitter that you are receiving from as to what you'll get:
- Heathfield | aerial horizontal - Broadcasts PSBs and COMs. COM4 (ITV3 etc) is on low power until 27th June on which date there is a retune for it. You might not get it until then.
- Hastings | aerial vertical - The COMs from Hastings use the same three frequencies as the PSBs from Eastbourne South Tower, so you may find them drowned out, or at least hit and miss, thanks to the interference.
- Eastbourne (South Tower) and Eastbourne Old Town (Jevington House, Upperton Road) | aerial vertical - These are PSB-only transmitters.
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Neil: The transmitters that serve your area have all switched to digital and all services are as they will stay.
To work out why you might not be getting ITV4, knowledge of which transmitter you are using may help.
First off though, see this page which lists all Freeview services (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
There are six multiplexes (groups) of services. ITV4 is carried on COM6. Are you missing COM4 and COM5?
Looking around on Streetview, there is a mix of Reigate and Crystal Palace. Both are in the same direction to a few degrees, but it is easy to identify which is which when you know how:
- If you are on Reigate then your aerial will be vertical (elements up/down). For Reigate you will probably need a wideband aerial to receive the three COM multiplexes. If you don't have a wideband aerial, this may cause poor or non-existant COM reception.
- If you are on Crystal Palace then your aerial will be horizontal (elements flat). For Crystal Palace a wideband aerial is not necessary and all channels should be receiveable using an aerial used for the former four-channel analogue.
The only thing to be aware of about Crystal Palace is that COM6 has a negative offset and other channels do not. There is a known issue with some devices which cannot receive the type of signals used after switchover (those in 8k mode) that have a negative offset. I won't explain what the negative offset issue is unless it turns out that you have an affected device.
If you are on Crystal Palace and find that you have COM4 and COM5 but not COM6, then post your make and model number and I will see if I can find out if it is a model that has the negative offset issue.
If you are on Reigate, then the negative offset problem cannot be an issue as Reigate's COM6 does not have a negative offset.
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Neil: I should point out that Reigate and Crystal Palace are nearly north east.
The predictor suggests that Midhurst and Heathfield could be possible and these are south west and east south east respectively. For both, aerials are horizontal.
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Owain: There should be no aerial upgrade required to receive Freeview HD.
Have you tried to receive it?
If so, what's the make and model of your TV or box?
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Owain: Are you definately receiving Welsh TV from Moel-y-Parc? And if so can you receive BBC and ITV1, S4C, Channel 4 etc? And are they good reception?
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Eddie: Freeview requires a terrestrial aerial, you can use Freesat with your existing dish. If you want a Freesat recorder, then you need two cables from your dish.
As you're only five miles from the Dover transmitter, you "may" be able to receive Freeview with a suitably placed set-top aerial.
This is particularly so if your window faces the transmitter and there aren't other buildings in the way.
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Eddie: I should point out that reception "could" be hit and miss with a set-top aerial.
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jb38: If this is the sort of affect expected with two overlapping SFN transmitters with different polarisations, then do you anticipate that if a national SFN was launched (such as that proposed on C36), that there will be lots of people with reception issues?
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Colin: How did you get on with your wire to the top of the hill?
It is possible that the COMs don't broadcast to the south. Maybe they couldn't get international clearance for them to do so.
The radiation patterns of the transmitters is secret, unfortunately.
See here for a list of multiplexes (those with a bullet in the "E"/England column apply): DMOL Post-DSO Multiplex Channel Allocations
What I suggest you do is focus on one service from each. I usually look for the first in each:
PSB1 (BBC One) = C24
PSB2 (ITV1) = C27
PSB3 (BBC One HD) = C21
COM4 (ITV3) = C25
COM5 (Pick TV) = C22
COM6 (Yesterday) = C28
So for COM4, look at ITV3 if it is tuned in on your receiver, or manually tune to C25 until you pick it up.
They installed a taller mast at Rowridge for DSO, so you could always go and ask if you can have a few sections of the old one to mount your aerial on.
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Tony: This is the two-tier terrestrial television transmitter network we now have, I'm afraid.
Icomb Hill only carries the Public Service Broadcaster (PSB) multiplexes (groups of services).
Those that it doesn't broadcast are the Commercial (COM) multiplexes and these carry the likes of ITV3, ITV4, Pick TV, Yesterday, Film 4 and Dave.
The COMs broadcast from 81 of the largest transmitters (largest by viewer population) and cover about 90% of the population. The other 1,000 or so relays, including Icomb Hill, are PSB-only. The cost to the COMs of including the relays in their portfolio would roughly double their cost of transmission whilst only adding about 8.5% of the population to their potential viewer-base.
As they are run entirely as profit-making ventures and have no "Public Service" obligation, they decided to turn down the offer of additional coverage.
See here for a further explanation:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
In some cases reception of COMs can be achieved from a station that carries them. Obviously this requires a new aerial and in some cases due to poor signal, a big aerial and sometimes big mast.
Failing that, the main option to get more channels is Freesat. There are some channels like Yesterday and Dave that are on full Freeview (COM) but not Freesat.
It's a common question and I believe that "Freeview Lite" has got to be the biggest let-down, particularly as mention of this inferior service doesn't feature in any of advertising. "Subject to coverage" fails to make clear that not all channels are available in all areas.
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The predictor does think that reception from Mendip "may" be possible in your post code. This does carry the COMs, although it has West regional BBC and ITV.
If you can receive the COMs from Mendip, then it would be theoretically possible to have two aerials and combine them (using a diplexer) into one downlead.
I put your post code into Google and the first house showed on Streetview (presumably at the centre of the code) has a Mendip aerial and an Icomb Hill one (photo taken in December 2009): GL54 2PN - Google Maps
Its height and size might be an indication of the sort of thing you will need. Obviously levels of reception can vary widely over a post code area and particularly so where the ground and surrounding ground isn't flat.
I understand that some receivers that have recording functions don't fair too well when receiving signals from more than one transmitter (scheduled recordings not starting). One way around this, if it proves to be the case, is to watch Mendip most of the time and switch to Icomb Hill for regional programming. For example, put BBC One from Icomb Hill on 800 and ITV1 Central from Icomb Hill on 801. Under such circumstances it might not be possible to reliably record from 800 and 801. This final paragraph is just a warning; it's what I've read.
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tina: If you have a booster, then you should remove it. This could be increasing your signal levels in excess of those that the BT Vision box (and any receiver) can handle.
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Jim O'Shea: There is the possibility that your receiver could have tuned to the Ramsgate relay instead of Dover. At the first stage, BBC comes on air on C26 and next week ITV1, C4 etc will be switched on on C23 and HD services C30. There are now Commercial services such as ITV3, Film 4 and Dave from this transmitter, so you are probably best advised to continue using Dover.
If you find that BBC is tuned to Ramsgate by looking on the signal strength screen, then you can avoid this by unplugging the aerial for the first 30% of the scan. This is probably good practice so as to avoid this as a possibility.
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Karen: See the message from Transmitter engineering added after your posting. Apparently the transmitter (BBC services at least) is (or was) of air from 10:01.
The BBC only reports on its own services. If this is due to a fault or a power failure, then obviously it will probably affect the independents as well.
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Gil: You should confirm that you are tuned to The Wrekin for HD channels. There appear a number of possibilities at your location and even though your aerial doesn't point their way, and in some cases is the opposite polarisation, you could be picking them up.
Click the Tradeview link next to your posting and view the channel numbers used by each transmitter for BBCB. Then check what you're receiving by looking at the signal strength screen whilst tuned to one of the HD services.
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R FLETCHER: You've posted this on the page for Darwen transmitter.
The problem you are experiencing is common in Eastbourne for people who are receiving from Hastings transmitter. See the Hastings transmitter page:
Hastings transmitter | ukfree.tv - independent free digital TV advice
The Hastings transmitter's Commercial (COM) channels, which carry the services you've mentioned, use the same channels (frequencies) as the relay on the top of South Tower in Eastbourne. Unfortunately South Tower only broadcasts Public Service (PSB) channels and these are those which you will still be able to receive from Hastings.
The only possible way to pick up the COMs at your location would appear to be Heathfield. Whether this is actually possible would have to be determined by an installer whilst on-site. However, the predictor suggests that it "may" be possible (this doesn't take into account local obstructions such as buildings or trees that may prevent reception).
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Gordon Ormston: The fact that analogue is very poor and snowy suggest that the problem isn't too high a signal level.
The bit about connecting loosing some signal was intended to be a crude attentuator to reduce the signal level.
Based on poor analogue reception, this would tend to suggest that you are in a poor reception area and not one where your receiver could be suffering from the effects of too much signal.
I used Megalithia to plot the terrain from the transmitter to your location:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
This suggests that you may (just) have line of sight, although bear in mind that ground levels for the plot are sampled at intervals and it may go higher within these samples. This also does not take into account any obstructions such as trees and buildings.
It could be that you have poor reception because of the umbrella effect. You will note that you are 100m below the ground that the transmitter is sat on.
Transmitters put their main beam out towards the horizon. Its strength helps carry it. Thus, the closer to the transmitter you are, the more likely it is that you will be under the main beam, as it were. But there should still be sufficient signal. But the issue you "may" have is due to being so low down.
Could you (can you) receive (the lower power) Freeview signals before switchover?
I'm not an aerial installer, so I'm not sure what else you could try.
Having read your comments, perhaps the only thing that you can do in an effort to receive terrestrial television is to get an aerial installer in. Or go with Freesat.
There are some channels that are on Freeview, but not on Freesat, e.g. Yesterday and Dave. However, these are carried on the (Freeview) Commercial multiplexes and these are on lower power than the Public Service ones from Dover. So you "may" find that you can only receive the Public Service channels from Dover, all of which are available on Freesat.
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Peter: Unplug the aerial for the first 30% of the scan to miss out Eastbourne's Group A channels.
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Peter: Try connecting a receiver directly to the aerial and work from there. That way you are discounting the possibility with the distribution amp and cabling causing an issue.
Once you have Heathfield channels tuned in your receiver's memory, then refer to the signal strength screen for one service on each mux.
This page shows the services by mux: DMOL Post-DSO Multiplex Channel Allocations
So focus your attention on:
- BBC One (PSB1)
- ITV1 (PSB2)
- BBC One HD (PSB3)
- ITV3 (COM4)
- Pick TV (COM5)
- Yesterday (COM6)
Of course, your aerial "may" always pick up Eastbourne even though it points horizontally to Heathfield simply because Eastbourne is so strong.
Some receivers store the first channels found during the scan, and more sophisticated ones choose which to go with by assessing strengths having completed the scan. Whilst you will hopefully achieve a result where Heathfield is the stronger, the latter "may" always be an issue.
Different receivers are designed in a different ways. Some have limited functionality when it comes to manual tuning, signal strengths and other technical information. It might be worth looking at what devices you have to see which might be most useful to help you site your aerial.
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Peter: Could it be the roof-tiles blocking the signal too much? Have you tried pointing the aerial out of the window (even if it's lower than the loft you are fitting it in)?
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Rob: Different receivers have differing sensitivies, and the signal may be marginal (i.e. a bit touch and go).
This is particularly the case as the Commercial multiplexes from Caldbeck (which carry Film 4 among others) are on low power until 24th October when Northern Ireland switches to digital. This is so as to protect against interference with its pre-switchover signals.
If your problem TV has manual tuning, then you need to manually tune to UHF channel 29.
Other possibilities include taking the problem TV to the aerial socket used by the other TV. Or if the TV aerial is fed via another box (e.g. a recorder), then try removing the box from the wiring so that the aerial socket is connected directly to the TV.
If the TVs are running off the same aerial and you are using a powered booster to split the signal, then try reducing the level of amplification (if it allows). If you can bypass the booster/splitter and connect the aerial to the feed directly to the problem TV to see if it makes a difference.
Once you have Film 4, Yesterday and other services on C29 (the "ArqB" multiplex), then don't retune. If you loose them then it is a problem with lack or too little signal and not tuning. Retuning is likely to result in wiping the services from the memory.
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Gordon Ormston: The analogue signals will be radiated from the antenna system at the top of the mast. Because of their high power, I assume that the main beam is higher (to the horizon) whereas the lower power signals are radiated from antennas lower down and because they are lower power, I "wonder" if the beam is aimed a little lower, which makes it better for you.
Obviously the post switchover signals are on a par with the old analogue ones, which is why I wonder if you're always going to have difficulty.
As I say, I'm not an installer and I'm not an expert on TV transmitters, but as a technically-minded person, I wonder if the above is your problem.
Maybe have a look around and see what your neighbours have with regards aerials, although obviously some may have been put up to receive pre-switchover signals (not that they won't work after, of course).
The only other thing is are there trees in the way of your aerial, because they could be shadowing the signal, a signal which may not be great in the first place (as suggested above). If so, could the aerial be moved to get a better view?
Or will a taller mast allow sight above the trees? I appreciate that the answer to this question may well be no, or may be "yes, until they grow a bit more".
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Gordon Ormston: I have looked at Riverside on Streetview and I can see the trees in the direction of the Dover transmitter. I can also see that the aerials on the two houses at the end of the road are pointing in roughly the opposite direction at Crystal Palace or Bluebell Hill (these being only a couple of degrees apart). Presumably they have given up on reception from Dover, although the tall large aerials show that their reception is very difficult.
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Craig: Look at www.aerialsandtv.com for information.
As Mark says, if you have a C/D aerial, then it will be unsuitable for Pendle Forest.
What aerial you need probably depends on what sort of signal you have. In the best areas, use a log which are naturally wideband, but have a flatter response than yagis.
If it's not so good, then a Group A yagi aerial as suggested by Mark might be what you're looking for.
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Rob: No problem. If you're looking for information and professional guidance on this, see www.aerialsandtv.com
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Bob: Yes. Yesterday and other Commercial services from Sudbury have been on low power. 27th of this month is the date for a retune when the strength of signals will go up.
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Floyd: A more specific location and direction of your aerial might be of help for us to identify which transmitter you are on.
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Tim Collins: The first thing to do is check that your receivers are tuned (on all channels) to Rowridge, and not another transmitter such as Whitehawk. Being tuned to another transmitter could cause such intermittent reception as the aerial will be pointing the wrong way for signals being received. If this is the case, and you are relying on a tree to reflect the signal back to you, then when the wind blows the tree moves and hence affects your reflected signal.
Refer to this page for a list of multiplexes and services carried on them (those with a bullet in the "E"/England column): DMOL Post-DSO Multiplex Channel Allocations
There are six multiplexes, so check one service from each to see what UHF channel (frequency) it is tuned to. (Previous analogue used one UHF channel per service.) Do this by bringing up the signal strength screen whilst on the service in question.
PSB1 | BBC One | RR=C24 | WH=C60
PSB2 | ITV1 | RR=C27 | WH=C53
PSB3 | BBC One HD | RR=C21 | WH=C51
COM4 | ITV3 | RR=C25 | WH=C57
COM5 | Pick TV | RR=C22 | WH=C56
COM6 | Yesterday | RR=C28 | WH=C48
RR=Rowridge, WH=Whitehawk
For example, go to ITV3 (number 10) and bring up the signal strength screen. It should say that you are tuned to C25 for Rowridge, but will be C57 if it's coming from Whitehawk.
If it turns out that you were tuned to Whitehawk for all or some multiplexes, and these were the ones causing the difficulty, then put the poor reception you experienced down to being tuned to the wrong transmitter.
Because Rowridge channels are low (in the 20s) and Whitehawk's are high (50s and 60), you can unplug the aerial lead at 30% through the automatic tuning scan to miss out Whitehawk.
If you were tuned to Rowridge whilst experiencing poor reception, then this could perhaps be co-channel interference from a transmitter on the Continent. In the days of analogue it was clear to see that another signal was interfering. When particularly bad, the other picture would be imposed over the one you're wanting to receive.
With digital, all you get is nothing. You "may" find that, where the signal strength screen indicates strength and quality, that you have a signal that is as strong as it is normally (might be worth making a note of strength on each multiplex when it's OK so you can compare) but with poor quality.
If the problem is on the COM multiplexes, then switching your aerial to vertical might help. Indeed, the likelihood of co-channel interference could be reduced where the interfering station broadcasts only horizontally.
Rowridge is the only main station that broadcasts horizontally and vertically. The horizontal component is primarily so as to work with existing aerials.
The PSBs are at a power of 200kW horizontally and vertically, whereas COMs are 50kW horizontally and 200kW vertically. One of the possibilities is that the marked difference in strength could be desensitising your receiver (so as to make it less sensitive to the weaker signals). For example, if your receiver is tuned to ITV3 on C25, it is therefore "looking" at C25. On C24 is a much stronger signal. When outside at night, and car headlights shine towards you, your eyes become less sensitive and therefore you are less able to see the darker surroundings until the car passes. This is obviously only a possible issue with receiving the three COMs from Rowridge.
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William Laverty: According to Digital UK, Newton relay transmitter will be operational after switchover.
However, it will be a Public Service (PSB) only transmitter (sometimes referred to as "Freeview Lite") and will not carry Commercial channels. PSBs carry BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services.
Freesat would give you all the PSB channels plus others. There are some which are available on full-service Freeview but not Freesat. See here for a comparison (ITV3 IS on Freesat):
Compare TV | ukfree.tv - independent free digital TV advice
Your existing dish will be suitable for Freesat. For each receiver (whether they be Freesat or Sky), you need a separate cable feed from the dish. This includes where a satellite receiver has a recording capability where one channel can be watched and whilst recording another.
The LNB is the bit on the arm that the cables connect to. This may need changing to give greater capacity (which allow more cable to be attached). For example, if you have a dual LNB, and you have two cables feeding your lounge, then you will need to have it replaced with a quad-LNB to allow four cables to be attached, they being the two you have now plus one for each bedroom.
The Freesat option is available now, so you don't have to wait until the terrestrial switchover in September.
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Linda Alba: The answer to the question and whether a retune is necessary in any case, depends on which transmitter you are using of which there appear to be a number of possibilities at your location.
It would also be useful to know which groups (known as multiplexes) you are now missing.
Refer to this page and work out which of the multiplexes you are missing: DMOL Post-DSO Multiplex Channel Allocations
I have talked about PSBs and COMs, and if you look at this page, you will see which services are on which multiplex. For example, ITV3 is on COM4 (SDN), BBC One is carried on PSB1.
PSB3 is the HD one, so for standard definition receivers it won't be present.
I had a look down your road on Streetview and could not see a single TV aerial, so am none the wiser as to which transmitter you may be receiving from.
The possibilities would appear to be as follows:
- Heathfield with aerial horizontal is to your east. This carries all six multiplexes. COM4 (SDN) remains on low power until 27th June when a retune will be necessary. Reception could perhaps be hit and miss until then.
- Haywards Heath with aerial vertical is to your north east. This only carries the three PSB multiplexes and therefore if you have tuned to or have ever tuned to the three COMs then you have been picking them up from elsewhere and thus reception could be hit and miss because your aerial points the wrong way. No retune is necessary for this transmitter.
- Midhurst with aerial horizontal is to your west. This carries all six miltiplexes and no retune is necessary.
For a picture of vertically and horizontally mounted aerials, see http://farm5.static.flick….gif
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Linda Alba: Depending on which transmitter you are using, and whether your receiver has manual tuning, then you may be able to restore the channels.
In order to work out what you need to tune to, we need to know which transmitter and which multiplexes you are missing.
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Hodgson: In your general area, signals can be received from a number of different transmitters. The first thing is to check that your receiver is tuned to the transmitter to which the aerial faces. To do this, bring up the signal strength screen and whilst on ITV3.
Here are the UHF channel numbers (equivalent to frequency) of the following transmitters:
- Tacolneston C42
- Waltham C29
- Sudbury C49
- Belmont C30
- Sandy Heath C51
If you don't know which transmitter your aerial is directed at, then let us know its rough direction and the UHF channel number that ITV3 is tuned to.
For some transmitters, a new aerial may be necessary, so knowing which transmitter you are using will allow advice as to whether this "may" be necessary.
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S R LOVEII: Further to Mark's comment, is the problem that there is no ITV1 or that there is, but it's the wrong region?
If there is an ITV1, then knowledge of its UHF channel (equivalent to frequency) might be useful. This is usually on the signal strength screen and will be a number between 21 and 68.
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MRS J: The fact that you are receiving different regional programming to which (I assume) your aerial faces and which you normally receive means that you are receiving signals from another transmitter. This is likely to be Sutton Coldfield. If you bring up the signal strength screen when on BBC One it will probably give you the UHF channel number (equivalent to frequency). For Sutton Coldfield BBC One is on C43. Likewise for ITV1, it is on C46.
There may be a workaround by unplugging the aerial during part of the scan so as to miss out scanning the unwanted channels and whilst scanning the wanted ones. Which channels you want depends on which transmitter your aerial faces. You've said that you aerial is on the roof, which is always a good place for it to be, but have alluded to its direction!
You've posted on the page for the Nottingham transmitter, but when I looked on Streetview, all aerials I could see were on Waltham. The Nottingham transmitter is situated at Kimberley and is intended to serve those who are unable to receive from Waltham, due to the topography.
Assuming that your aerial is directed to Waltham, then run the automatic tuning scan and unplug the aerial when it gets to 30%. Then plug it in again when it gets to 55%.
Once you have finished, (looking on the signal strength screen) BBC One should be tuned to C61, ITV1 to C54, BBC One HD (if applicable) to C58, ITV3 to C29, Pick TV to C56 and Yesterday to C57. (These channel numbers are those used by Waltham.)
If any of these are incorrect, then post back telling us what they are and I will see if I can suggest something else to try.
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Trevor Wright: The Commercial channels are on low power from Sudbury. Since last November there have been many reports through this website of people unable pick-up C63.
The changes due to happen this Wednesday will see all of Sudbury's Commercial multiplexes going to full power (finally!). As you know, this is around a year since Sudbury switched, but it has been in this "temporary" low power state.
For this reason I suggest that no changes be made until then, when an assessment of reception of the final-state signals can be made.
The three Commercial multiplexes will use 56, 58 and 60 which are above the former analogue Group B channels, and so may be outside the officially-designed range of many aerials, but because digital reception is all about getting sufficient level above the threshold, then this "may" work fine when the signals go up to full power.
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Monday 4 June 2012 10:01PM
David Hemsworth: Lost channels after powering off is usually down to the receiver's memory being full. During the automatic tuning procedure, it scans frequencies from low to high. When it finds a signal, it stores it, and this includes signals from other transmitters (where they are present).
Consequently, where there are other lower signals present, and the ones you want are at the higher end of the band, the highest ones could suffer from being "forgotten". The workaround is therefore to get it so that it doesn't store the lower channels that you don't need.
This is the theory and you will have to test to see if that is the cause of the problem in your case.
I assume that you are receiving from Heathfield. What I suggest that you do is run the automatic tuning scan with the aerial unplugged up to 50% (or up to UHF channel 44 if it gives them when scanning). That way you will have it unplugged when scanning other transmitters. This will miss out ITV1, Channel 4 etc from Heathfield, but I'll come to that in a moment.
The test is to see if preventing other (non-used) signals from being stored will allow BBC to be stored. So power the set off as you would normally and then on again and see if it has remembered the channels it normally forgets.
If it has, then, if it has manual tuning, go to it and tune to UHF channel 29 to restore ITV1, Channel 4, Channel 5 etc.
If this works, then come 13th, start the automatic tuning scan with the aerial unplugged up to 35%. There should be no need to manually add any channel because they will all be in the window above 35%.
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ArqB multiplex which carries Yesterday, Film 4, ITV4 and others is as it was. The apparent lower strength may be due to the fact that the high power BBC multiplex is on a neighbouring frequency. The high power signal could be desensitising the receiver to the lower power ArqB signal.
It's like being out when it's dark when there are car headlights shining towards you. Your eyes will become less sensitive and it will be more difficult to see what's going on around the lights.
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And finally, there will be another retune event on 27th June when the SDN multiplex which carries ITV3 etc changes frequency. Until then, its transmission power will remain as it is now. You may find that it appears weaker, for the same reason as ArqB is now; that is the new high power signals will be on adjacent channels.