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Archive (2002-)
All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.Tony Ashby: I should point out that your are missing a single multiplex.
Refer to this page for the services by multiplex (those with a bullet under "E"/England apply):
DMOL Post-DSO Multiplex Channel Allocations
As you have ITV3 and Yesterday, you must have COM4 and COM6.
For the UHF channel numbers of each of the multiplexes from Hastings, follow this link (click the word "Hastings") to its transmitter page.
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Campbell Thomson: I understand that the BT Vision box is not a HD receiver and therefore the HD services are not receivable with it.
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Tim Collins: We can't be totally sure that this is co-channel interference. Even if the interfering signal were to be strong enough to show a picture, it won't because your receiver is waiting for the signal from Rowridge.
If you are tempted to rescan, then you "might" find a foreign multiplex on the channel that you are having difficulty. Obviously retuning isn't advised in such circumstances as it will leave you without the receiver tuned to what you want, so it's up to you.
The thing with inversion is that it isn't that the signal travels further, but that the signal which normally goes up into space gets bounced back down to earth:
High pressure causing channel loss through "Inversion" | ukfree.tv - independent free digital TV advice
This page might be of interest:
Rowridge Transmitter
This PDF lists transmitters in France:
http://tvignaud.pagespers….pdf
Most are horizontally polarised and those that are vertically polarised are low power ones, so won't be an issue with inversion. The "PAR" column gives the power in kW. R1 through to R6 and L8 are the multiplexes.
Having your aerial vertically polarised should help "rejection" of interfering horizontal signals.
Obviously get in a professional or at least someone who is proficient in going on the roof safely.
The reflection I was thinking of was that of Whitehawk, perhaps on another building reflecting back to your aerial (which faces the other way), although I said that without thinking that Whitehawk is vertical only and your aerial is horizontal, so that's unlikely.
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Mazbar: Of course water getting into a cable needs sorting, irrespective of any other factor that may be affecting reception.
I don't recall advising anyone to check their aerial. The nearest I have gone to this is advising people using Rowridge that switching their aerial to vertical may help. Granted, a qualification that this should be done by a professional or at least someone proficient in going up on to the roof safely may be wise.
As you say, there are some who are not suitably qualified in going on the roof and unable to appreciate that, as a result, they should not go on the roof.
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Tony Ashby: It difficult to say how it might have arisen. I would be much more concerned should you loose reception of this or any other multiplex.
The only logical explanation is that you lost reception of COM5 when you did the scan. Whether this is indicative of the possibility that you may have hit and miss reception, only time will tell.
Dave HD is not available on Freeview and isn't likely to be soon (if ever)!
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Campbell Thomson: If your window faces the west (at the end of the building), and you are high up, it might be worth trying a set-top aerial to see if the Commercial channels (those that Newhaven doesn't carry) can be picked up from Whitehawk Hill, which is adjacent to Brighton Racecourse.
Between you and Whitehawk is the ridge to the west of the Ouse at Newhaven (which is where the Newhaven transmitter sits). This ridge is reducing the likelihood of reception from Whitehawk at your location (due to it being in the way). At around about 40m to 50m off the ground you are about the height required to "see" Whitehawk over this ridge. Thus, the lower you are, the more you sit behind it and lower your chances of reception are.
If you have a digital (Freeview) TV that allows manual tuning, then it might be worth pointing a set-top aerial towards Whitehawk and manually tuning to UHF channels (equivalent to frequencies) 57, 56 and 48 which is what the three "missing" groups of Commercial channels are on from this transmitter.
As Whitehawk and Newhaven are inline with one another, if you do successfully manage to get these three (Commercial) channels, you may be able to tune to Newhaven for the other (Public Service) channels, so as to give you ITV Meridian Maidstone (Whitehawk broadcasts ITV Meridian Southampton). This may require a little trickery to achieve, but the first thing would be to see if 57, 56 and 48 can be picked up from Whitehawk.
I understand that BT Vision boxes don't have manual tune, so this may be more difficult. Using a TV or box with manual tune might be useful to test for reception in the first place.
It is worth mentioning that set-top aerials can be hit and miss. Sometimes they can work well and in other places they can work at times and not at others. But desparate times call for desparate measures.
I have one of these Labgear ones (other sellers are available!) that I use if a fixed aerial isn't available:
Set Top Aerial Labgear | eBay
You should have the aerial set vertically for Newhaven and Whitehawk. It should be pointed in the direction of the narrower end (the end which the wire is attached).
Failing reception from Whitehawk, I'm not at all sure whether it may be possible with a set-top aerial at 64 miles, but Rowridge on the Isle of Wight is 30 degrees anti-clockwise of Newhaven and Whitehawk and its three Commercial channels (for manual tuning) are 25, 22 and 28. Again, your aerial should be vertical for Rowridge. If this works, you may well be able to tune to Newhaven for Public Service channels with the single aerial.
As I say, all the above may be a last-ditch attempt at receiving the full Freeview service, which obviously carries no guarantee of reliable reception. If you're on the first few floors or face north-east or south-east only, then chances are practically non-existant.
If you do try this it might be worth turning off your Home Hub if it's near by, so that the wireless part isn't likely to interfere. Same goes for Power Plugs if you have them. If you manage reception and find that you loose it when the Hub is switched on, then you will have to look at relocating it.
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Campbell Thomson: I'm not a qualified professional on TV reception but a technically-orientated person and as such I generally try things to see if they work.
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Campbell Thomson: If you have a TV or box with manual tuning, attempt a manual tune to UHF channel 48 (from Whitehawk) with it connected directly to the roof-top aerial.
And look in the 800s to see if there are any of the "missing" Commercial channels like ITV3, Pick TV and Yesterday.
Newhaven now uses channels 40, 43, and 50. For the former analogue it used 39, 41, 43 and 45.
If the aerial system has a filter in place and it lets all channels through in the range of Newhaven, then it "might" also let through 48 as it is within the range used by Newhaven. C48 from Whitehawk carries the two Sky Sports channels which I understand are part of the BT Vision service.
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Nick: Sudbury's COMs' power goes up this Wednesday which is when Dover completes switchover.
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Nick Cleave: Where does your aerial point? If it is directed to the Dartmouth relay transmitter (which appears most likely) then it does not broadcast ITV3 or any of the other Commercial multiplexes.
Refer to the list of Freeview services by multiplex (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
There are six multiplexes, including PSB3 which is the HD one (and is therefore unavailable for non-HD receivers).
The Dartmouth transmitter on Waterpool Road only carries the Public Service (PSB) multiplexes and isn't ever likely to carry the COMs because those Commercial broadcasters don't wish to invest in the small transmitters because they don't see it as worthwhile.
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Harish: If your aerial is directed to Bluebell Hill, then manually tune to C24.
If you have no joy, then wait until this Wednesday when Bluebell Hill completes switchover and ITV, C4 and C5 go to full power.
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H. Brown: The fact that you are receiving London programming is crucial and shows that your receiver is tuned to another transmitter - Crystal Palace. This explains why you may have poor reception; because the signals being received are from a different direction to which your aerial faces.
When the receiver performs the automatic tuning scan, it looks through UHF channel numbers (equivalent to frequencies) from 21 to 69. All of Crystal Palace's are in the 20s and 30, with Sudbury's lowest being 41 up to 60. Tacolneston's are interleaved with Sudbury's.
So to avoid Crystal Palace, have the aerial unplugged for the first 30% of the scan (or until it gets up to UHF channel 35 if it gives these during scanning).
There is, of course, always the possibility that, having dealt with Crystal Palace, there is another transmitter that is favoured over Sudbury. You will have to deal with that should you find it. It is a good idea to confirm that all is tuned correctly to the desired transmitter, so as not to find out when you want to watch something that reception is poor because it is incorrectly tuned.
See here for a list of multiplexes (three PSBs and three COMs) which are groups of services (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
From Sudbury there are six multiplexes, each taking up one UHF channel. Each former analogue service used one UHF channel.
For one service from each multiplex, check that it is tuned to Sudbury by looking on the signal strength screen:
PSB1 | BBC One | C44
PSB2 | ITV1 | C41
PSB3 | BBC One HD | C47
COM4 | ITV3 | C58
COM5 | Pick TV | C60
COM6 | Yesterday | C56
Here I have given the first service within each multiplex (see the link for the full list).
For example, bring up Pick TV (number 11), and then bring up the signal strength screen. It should say that it is tuned to C60 for Sudbury. If it is C45, for example, then it is tuned to Tacolneston instead.
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Alan Reed: No, Eastbourne South Tower is a Public Service relay only. This is because the Commercial broadcasters don't wish to pay to transmit from small sites like this because they consider it not worth the expense.
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Nick Anderon: I assume that your native transmitter is Bluebell Hill.
The fact that you are receiving London means that your receiver has tuned to Crystal Palace.
Unplug the aerial for the first 30% of the automatic tuning scan to miss out Crystal Palace frequencies.
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Peter: Ensure that 5* is tuned to C58 which is the signal from Sudbury. This information is usually given on the signal strength screen.
If it's not, post what it is and I will see if I can suggest a workaround.
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MW: No. The Commercial broadcasters do not wish to invest over a 1,000 small transmitters like East Grinstead.
They achieve 90% coverage from 81 of the largest transmitters (largest by viewer population). To include the small transmitters would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer base.
They have no "Public Service" obligation and operate purely for profit.
The only thing you can do is investigate the possibility of receiving from another transmitter that carries the Commercial channels. In some cases this may mean going to some lengths.
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Collette Murphy: The Licence Fee does not guarantee reception of signals and it does not provide support with reception issues.
If you are using a television receiver, then by law you must have a TV Licence. If you sell all your receivers, then you can stop paying your TV Licence.
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Julian Fraser: You can't really compare signal strength meters between devices. However, you can compare the strengths of the different multiplexes with the same device. See if 56 and 58 are quite a bit lower than BBC and ITV on 44 and 41 respectively. This would tend to suggest that your Group B aerial is not good enough for C60 which quite a bit out of group.
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IJB97: Unplug the aerial for the first 30% of the automatic tuning scan to miss out signals from Crystal Palace.
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Andy, otford: You've posted on the page for the Otford transmitter. If your aerial is directed at it, then it's a wonder you ever received Dave anyway because it doesn't broadcast it. In which case you need to look at getting an aerial on Crystal Palace.
If your aerial points to Crystal Palace, then I suggest that it could be the Inversion effect in play. By retuning you have shot yourself in the foot because you will now not know when the effect has lifted and you will need to keep retuning until it comes back. Had you left it then you would have simply been able to select Dave.
For Dave you need to manually tune to UHF channel 22, if your receiver allows.
Otford transmitter is north east from you on Otford Mount. Aerials are vertical.
Crystal Palace is west north west from you and aerials are horizontal.
See this picture for a photo of aerials polarised horizontally and vertically:
http://farm5.static.flick….gif
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Syd Wall: There were some retunes caused by changes made at a number of transmitter sites in the early hours of yesterday morning, but these were further east and affected some of Anglia and South East areas.
If you can get the message to go away (by pressing "OK" or similar), then you can probably ignore it.
I wonder if your receiver has, in addition to your native transmitter, found and stored signals from Sandy Heath which is an Anglia transmitter. Of the Anglia region, it was the Sudbury transmitter that was affected by the retune (not Sandy Heath). I wonder if the message you are seeing is one which was broadcast over the air from all Anglia transmitters, simply because it is not possible to have the message broadcast only from Sudbury (because perhaps they all have to carry the same message, as it were).
I'm not too familiar with how these things work; just a technical bod giving you my thoughts of what I would see as a possibility. If it continues, then you will have to look at a solution. The worst case solution is obviously to carry out a full retune, but I wouldn't do it at this stage. If it does continue, something to try before doing a full retune might be to add new services (or similar) if your receiver has such a function.
As I say, these are possibilities if the message doesn't go away. But what I can say for certain is that there were definately no changes to Lark Stone and Sutton Coldfield transmitters that would require a retune.
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Derek: A number of people have reported difficulty with signals from Crystal Palace and it is believed that this was due to the inversion effect, so there is probably nothing you can do.
Assuming no local obstructions like trees and buildings, you appear to have line of sight with the transmitter. Where that is the case, at 18 miles from a transmitter of the power of Crystal Palace, there should be no need for a high-gain aerial.
See this link for a plot of the terrain from you to CP:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Follow the link below the trace for a map with a line joining the two points (which may not be exact).
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IPG Derwent: This is correct.
Unfortunately the UK now has a two-tier terrestrial transmitter network. It is likely that viewers will wish to receive from full service transmitters where possible.
Leamington Spa transmitter only carries the Public Service channels because the Commercial broadcasters don't wish to invest in it.
Looking on Streetview, there are buildings on the other side of Coventry Road receiving from Sutton Coldfield, and these are as high as yours, so it may be a possibility.
Obstructions such as buildings and trees can cause difficulty with reception. However, your chances could be increased by virtue of the fact that you are in a two-storey building.
Some aerials, particularly those installed in the days of four-channel analogue, only work with certain bands of frequencies (those frequencies that the designated transmitter uses/used). Should this be the case then a Leamington Spa aerial won't be suitable for Sutton Coldfield. If it is a wideband, then it will be suitable.
Recepion from Lark Stone would appear extremely unlikely, according to the Digital UK predictor.
I suppose that it will probably be down to your landlord to do something.
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Adrian Sankton: That is correct; there were no changes to the transmission power.
The S1 antenna was to protect against interference with transmitters in Kent until they switched over. This is because they used the same frequencies pre-switchover.
It affected the signal in that general direction, focusing it lower down to the horizon so as to curtail its propagation (in that direction).
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Tony Adams: During the automatic tuning scan, it looks at UHF channels (equivalent to frequencies) from 21 to 69.
Crystal Palace (London) uses channels in the 20s and number 30. Bluebell Hill uses channels ranging from 39 to 54.
You can therefore avoid Crystal Palace by unplugging the aerial for the first 30% of the scan. However, if the Anglia transmitters you are picking up are Rouncefall and Sudbury (these operate using the same frequencies), then you can't avoid them without missing out some of Bluebell Hill's.
Rouncefall/Sudbury uses 44, 41 and 47 for BBC, ITV1 and HD respectively.
If you can wipe the channel memory altogether and manually tune, then do that.
For Bluebell Hill you need to tune to:
46, 43, 40 (HD), 45, 39, 54
If you can't wipe the memory, perhaps by starting the automatic tuning scan with the aerial unplugged and maybe stopping it just after it has started, the objective being to "blank" what's stored. Or maybe run the automatic tuning scan through fully with the aerial unplugged.
If you have it all tuned in but wrong (e.g. you have BBC London), then it may well have put Bluebell Hill in the 800s. Therefore, when you manually tune to Bluebell, it may do nothing because as far as it is concerned, it has tuned to Bluebell.
Failing that, run the scan with the aerial unplugged up to 55%. This should pick up C54 from Bluebell which is COM6 (Yesterday etc) ONLY.
Refer here for services by multiplex (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
If at this point you only have those in COM6, then manually tune the other four (or five if you have a HD receiver).
The numbers I gave above are in order of multiplex.
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Linda Taverner: When you say "all are the same" if you are saying that all flats have no signal, then this clearly indicates a problem with the aerial system. You probably need to raise this with your landlord.
There was a retune required (from) yesterday for Heathfield for ITV3 and some other services. This only affected a small proportion of services and did not affect BBC, ITV1, Channel 4, Channel 5 (and quite a few others were unaffected).
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Mike Gordon: I think that this might be the inversion effect which is caused by the weather causing signals from another transmitter to reach your location.
There was definately no retune for Crystal Palace and there is not one sceduled this year or next, so under such circumstances it is NOT advised to carry out a retune as all this can do is cause the services to be lost from the receiver's memory.
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Mrs Thompson: Unfortunately Henley-on-Thames transmitter does not carry the Commercial channels and is not likely to.
The Commercial broadcasters cover 90% of the population by transmitting from 81 of the largest sites (by viewer population). There are over 1,000 small "filler-in" relay transmitters like Henley and for them to include these would roughly double their cost of transmission whilst only adding about 8.5% of the population to their potential viewer-bases.
As they operate to generate profit by selling advertising which they show to viewers, they don't consider it worth it. What you get from Henley are the Public Service channels only. The Commercial broadcasters have no "Public Service" obligation.
The difficulty with receiving from Crystal Palace in your area is due to the fact that it is in a valley. This is why the Henley transmitter was installed.
In some areas it "may" be possible to receive from Crystal Palace, but this could vary house by house. And in any case, a substantial aerial may be needed.
I went along Reading Road on Streetview and most aerials were on Henley. A few were on Crystal Palace.
The two transmitters are in almost the same direct, but it is easy to tell which an aerial is pointing to as Henley's are vertical and Crystal Palace's are horizontal. See this picture:
http://farm5.static.flick….gif
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Kate: If this has just happened now (in the evening), then I suggest that it isn't scheduled maintenance.
Arrow and Heart broadcast from the Hastings transmitter on 107.8MHz and 102MHz respectively.
The most common reason that a transmitter goes off the air is a power failure. The fact that TV and FM are off air makes this a possibility in view of it not appearing to be scheduled work.
BBC Reception says no problems for Hastings, so maybe it's only just happened.
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Andy Slater: Read my response to another person in Stroud:
Top questions | ukfree.tv - independent free digital TV advice
Bring up the signal strength screen whilst on ITV3, Pick TV and Yesterday and see which UHF channels they are tuned to.
Refer here to see the three COM multiplexes:
DMOL Post-DSO Multiplex Channel Allocations
ITV3, Pick TV and Yesterday are on COM4, COM5 and COM6 respectively.
Maybe you are picking these up from Wenvoe. If you are, then you find that they are on C42, C45 and C49 respectively.
Or from Mendip they are on 48, 52 and 56.
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kate: As the FM stations are off the air as well, I think that the weather is unlikely. Are all Freeview channels off?
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Kate: I don't know then.
Check that for PSB1 and PSB2 that you are tuned to Hastings.
Bring up the signal strength screen on BBC One and check that it is tuned to UHF channel 25 and for ITV1 that it is C28.
Depending on your location, there are other possible PSB transmitters that your receiver could be picking up instead. Where this is the case, then it needs correcting.
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kate: The most likely C24 signal is that from Rowridge which on the Isle of Wight and is the main transmitter serving a large portion of the south coast.
Sometimes it's possible to unplug the aerial for part of the automatic tuning scan to miss out unwanted signals. However, Rowridge and Hastings all use neighbouring channels.
If you can wipe your tuner's memory, and manually tune to Hastings, then that is probably the best thing to do. Whether you can do that depends on the design of the device.
For Hastings you need to manually tune:
25, 28, 22(HD), 23, 26 and 30
See above for which services each carries.
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Rosemary: See the page for the East Grinstead transmitter (follow the link).
For people whose aerials face the East Grinstead transmitter, there are no Commercial channels which include services on numbers 10, 12 and 15. This is because it carries Public Service channels only.
If those people (who have aerials pointing to East Grinstead) received any Freeview before switchover, then they MUST have been picking it up from another transmitter as East Grinstead did not broadcast any Freeview before switchover.
Transmitters that carried (full) Freeview before switchover carry fulll Freeview after switchover. In general terms, those who could receive pre-switchover Freeview can receive the stronger post-switchover full Freeview. However, where this was/is done using an aerial that faces another transmitter, then intermittent or no reception is possibility and whilst the bit about picking up Freeview after "may" apply, it's much less cut and dry. At the end of the day, in such cases the aerial is being used for something that it wasn't installed for; is installed to receive from the transmitter that it is directed.
Of course, there may be areas of East Grinstead that have aerials directed at another transmitter, such as Crystal Palace, and they would be expected to be likely to get the full service.
Obviously I can only be very general. However, the first question I would ask is where does the aerial point?
- If it points to East Grinstead transmitter, then only the Public Service channels will be available. East Grinstead transmitter is to the south of the town on Saint Hill. Aerials will be vertical.
- If it points to another transmitter such as Crystal Palace, then the full service should be available and it therefore warrants further investigation as to why it might be that the Commercial channels aren't available.
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Corin: Please do not take my quote out of context!
I advised that the best thing NOT to do when there are lift conditions is retune. You may end up either loosing services or getting ones tuned in from the distant transmitter whose signal is interfering from the one you want. This could even be a foreign one.
Please explain how this is beneficial...
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Steve F: Check that you are tuned Sutton Coldfield for BBC, and not The Wrekin. Do this by bringing up the signal strength screen whilst on BBC One. It should say C43 for Sutton Coldfield and not C26 which is The Wrekin.
If you find that you are tuned to The Wrekin, run the automatic tuning scan with the aerial unplugged for the first 30% to miss out scanning of The Wrekin's channels.
If it is tuned to Sutton Coldfield, then maybe it is the signal level which is verging on being excessive. See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Bibby: Try again tuning the HD services. I have read reports on here of people with the same issue and someone even suggested that once switchover happened in the South East, HD wasn't being broadcast. Someone has posted this morning to say that they have retuned today and are now picking up HD from Tunbridge Wells transmitter.
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Roland Rippingale: HD Ready means that the TV can show HD pictures but does not have the means to receive HD signals. Follow the link by clicking the words "HD Ready".
In order to show HD pictures broadcast after switchover, each TV will require a separate receiver (box).
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Adrian Durrant: Unfortunately the UK now has a two-tier terrestrial transmitter network.
Those who can only receive from Eastbourne South Cliff Tower will only ever receive the Public Service (PSB) channels, as will around 8.5% of the population. This is because the 1,000 or so small relays like Eastbourne only carry those channels and of the 81 transmitters that do carry a full service, some viewers will only pick up the Public Service channels. The transmission power of the COM channels from Hastings is lower than that of the PSBs.
The general plan is that Public Service channels are receiveable after switchover without need to change aerial. Some people will require a different aerial to receive COM channels as well.
As part of switchover, UHF channels 31 to 37 were ringfenced to be sold off to three more Commercial operators, whose future networks will no doubt mirror those of the current quasi-national Commercial networks.
Had these channels not been set aside, then there would have been more available and hence clashes like which exists in the Eastbourne area with reception of the COM signals from Hastings transmitter would have been less likely.
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Adrian Durrant: Digital reception either works or it doesn't; there is very little in the middle, hence people talk about the "cliff-edge".
You may find that sometimes it works and at other times it doesn't, either because the interference from Eastbourne is a little stronger or because the signal isn't quite as good from Hastings or a bit of both.
If you are in an area with good reception of Heathfield, then that might be a better bet. If your Hastings aerial is a Group A one, then it won't really be suitable for Heathfield. However, as Hastings' pre-switchover digital signals were not all in Group A, I suspect that there is a fair chance that you have a wideband aerial, and this will be suitable for Heathfield, so long as it is sensitive on its Group B channels.
Failing that, you may be able to have the aerial mounted where it gets sufficient signal from Hastings, but where it is screened from Eastbourne, for example by mounting it on one side of the house and using the house to block the unwanted signal.
Obviously any changes should only be carried out by someone who is proficient at going up on to the roof in a safe manner.
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Ian: I gather that you're receiving from Dover.
The signals are as they will stay. In some cases the Commercial channels are lower power than the Public Service ones (see below).
See this page for the six multiplexes (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
There are three Public Service Broadcaster (PSB) multiplexes and three Commercial (COM) ones.
Sky News and Yesterday are on COM5 and COM6 respectively. Is COM4 affected?
Do you know what UHF channel you have been picking up TF1 one? This information is usually given on the signal strength screen.
Maybe the problem is interference from another transmitter caused by the lift conditions.
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The plan is to have the PSBs cover the same areas as the former four-channel analogue. The COMs coverage is reported as being 90% of the population, versus 98.5% for the PSBs.
Even for transmitters like Dover which carry the COMs, their reach won't be as good as the PSBs from the same stations.
The COMs use a mode of signal that is less robust than the PSBs and this is so that they can squeeze more services in. By "less robust", think of sending a fragile package and a non-fragile package via a carrier that throws parcels around. Whilst the non-fragile package gets to its destination without damage, the same cannot be said for the bone china in the fragile one.
So where the signal (the carrier) isn't as good, the COMs are more likely to get broken whereas the PSBs aren't.
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Adrian Durrant: If you do decide to realign your aerial to Heathfield, then you could always add attenuation if the signal level received turns out to be too high.
In any case you will probably be able to split the signal to serve multiple rooms using an unpower splitter:
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
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Mike B: For Belmont you may need your old (Group A) aerial replacing with a wideband one because two of the six multiplexes are well out of that Group. A fuller explanation is below.
Whilst the cable might not be the double-screened stuff used for satellite installations, it may well be OK, or you may decide to replace it or have it replaced. It is the aerial the is most likely to be the difficulty.
I would try it and see. Digital reception requires sufficient signal strength to achieve reliable good quality. The objective is NOT to get the strength bar as close to 100% as possible.
Refer to this page for the six multiplexes (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
You may find that COM5 and COM6 are unavailable or poor. The three PSBs and COM4 should be OK as they are all in Group A from Belmont. This means that your current aerial will be expected to receive the HD services.
I suggest that you focus on the first service from each multiplex, ensuring that they are good and tuned in correctly. They are (including UHF channel numbers for Belmont):
PSB1 | BBC One | C22
PSB2 | ITV1 | C25
PSB3 | BBC One HD | C28
COM4 | ITV3 | C30
COM5 | Pick TV | C53
COM6 | Yesterday | C60
For example, ITV3 is the first service carried on COM4. Go to it and bring up the signal strength screen and check that it is tuned to C30. These checks give you confirmation that your receiver is tuned to Belmont and not another transmitter.
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TV frequencies (known as channel numbers 21 to 69) are divided into three main Groups. Group A is the bottom third and the former four-channel analogue signals from Belmont were all in Group A. As a result aerials whose sensitivity was greatest on those channels were installed.
Channel 5 analogue from Belmont was lower power and therefore weaker and was also well out of Group, being on C56 which is the top third (Group C/D). After switchover, COM5 and COM6 are on 53 and 60 which may mean that your aerial isn't sensitive enough to pick them up.
For an explanation of aerial groups, see:
Aerials, TV Aerial and Digital Aerial
If you are looking at DIYing, or just want to be more informed before calling in a professional, see:
Belmont TV Transmitter
The obvious caveat that working on the roof or at height can be dangerous applies and the job should only be attempted by someone who is qualified and has the appropriate ladders.
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Adam: Which transmitter is your aerial pointing to? Is it Bluebell Hill?
If so, check that it is tuned to it for all channels. It could perhaps have tuned to the Faversham transmitter for BBC and ITV1 (this transmitter does not carry the Commercial channels ITV3, Pick TV, Yesterday etc). Or maybe it has tuned to Crystal Palace which is a few degrees off beam of Bluebell Hill.
For each of the following, bring up the signal strength screen and check they are correct (this assumes Bluebell Hill is the desired transmitter):
BBC One = C46
ITV1 = C43
BBC One HD = C40 (if applicable)
ITV3 = C45
Pick TV = C39
Yesterday = C54
BBC One could perhaps be tuned to Faversham on C21, Crystal Palace on C23 or maybe Rouncefall on C44.
If you find that it is tuned to one in the 20s, then the solution is simple; just run the automatic tuning scan with the aerial unplugged for the first 30% of the scan. This is because, as shown above, Bluebell uses those in the 40s and 54.
The scan runs from 21 to 69 so if it only gives a percentage as it progresses, then you can get a rough conversion to find out where to plug in the aerial.
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Sandie: If you are using a separate set-top box, the issue could be because it has its own volume control.
From what you describe, it sounds as if you have the volume set to high or maximum on the TV whilst having the volume of the box very low.
The volume control on the box's remote (if there is one) operates the volume for the box and the volume on the TV's remote operates the volume on the TV. They are independent of one another.
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barry woodward: There is no such thing as a "digital aerial". Aerials work based on frequencies used and don't care whether signals are of analogue or digital form.
In some cases aerials need to be replaced because the signals used for post-switchover digital are different to those use for former analogue.
If you post your location, preferably in the form of post code or nearby post code (e.g. a shop), then we can advise whether you will be likely to be affected. It is generally a good sign that it works now, but knowing which transmitter you are using will help us to be more sure whether your current aerial is likely to work after switchover.
If you know which transmitter you use or which direction your aerial points, that may help, along with the location.
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Dale: See
Why do the six Freeview "multiplexes" have twenty different names? | ukfree.tv - independent free digital TV advice
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Richard: I imagine that it is likely to be the lift conditions. See the page on the inversion effect.
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Les Beynon: The reason is because ITV4 is carried on one of the Commercial multiplexes. A multiplex is a digital signal that carries multiple services.
The operators of the Commercial multiplexes (known as the "COMs") can choose where to transmit from. As they are run purely for profit the have opted to invest in 81 of the largest transmitter sites (largest by viewer population). This gives them a 90% coverage of the population.
For them to transmit from the 1,000 or so small relays like Newhaven would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer-bases. When the objective is to sell advertising which they show to as many viewers as possible at lowest possible cost, it is easy to see why they aren't interested in the relays.
The multiplexes that Newhaven carries are the Public Service Broadcaster (PSB) ones. The Commercial broadcasters have no "Public Service" obligation which is why the UK now has this two-tier terrestrial transmitter network.
Freesat is probably your best bet for additional services, including ITV4.
See here for a comparison of full Freeview vs Freesat:
Compare TV | ukfree.tv - independent free digital TV advice
ITV3 IS on Freesat, despite its logo appearing on that page.
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Jan Gibson: It is a possibility that your aerial needs replacing in order to pick up some or all of the Commercial (COM) multiplexes.
Refer to this page for the six multiplexes which are groups of services, each carried on a single signal:
DMOL Post-DSO Multiplex Channel Allocations
ITV4 is carried on COM6 multiplex (known as "ArqB") which is on UHF channel (equivalent to frequency) 56 from Sudbury. Aerials fitted during the days of four-channel analogue (or even three-channel analogue !) will probably be less sensitive at frequencies used by the COMs. This may or may not prove to be an issue.
Assess which of the multiplexes are missing and which you have by referring to the above page and checking to see if the services on each are present.
If your receiver has manual tuning, then it is worth attempting to manually tune them. Depending on the design of the device, it may indicate whether there is a signal there, but just not strong enough.
For Sudbury:
COM4 (SDN) | ITV3 etc | C58
COM5 (ArqA) | Pick TV etc | C60
COM6 (ArqB) | Yesterday, ITV4 etc | C56
The "C" numbers are UHF channel numbers that you need to input whilst on the manual tuning screen.
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Your aerial will probably be a Group B one which means that it is most sensitive on the middle third of the band of frequencies used for TV. Sensitivity drops off outside this; it doesn't stop totally, but may be noticeably lower.
Whilst the Public Service channels (BBC, ITV1, C4 etc) are within Group B, the COMs are above it (top third known as Group C/D).
For this reason you may need your aerial replacing with a wideband one which is suitable for the whole band, or a Group E one which is the top two thirds of the band (which are Groups B and C/D combined).
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peter bingham: Assuming that you are receiving from Winter Hill, then there is a retune scheduled for next April when PSB1 (BBC standard definition services) changes from C62 to C50 and COM5 (Pick TV etc) changes from C61 to C49.
This is connected with the clearing of channels 61 to 69 for 4G mobile services. I don't know whether there will be likely to be any further changes necessary.
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Katharine: See the posting I've just made to Jan Gibson who is also using Sudbury:
Freeview reception - all about aerials | ukfree.tv - independent free digital TV advice
Your aerial may need replacing if it is a Group B one. Before Wednesday, the COM4/SDN multiplex which carries ITV3 was on a frequency within Group B and now it is not, so that could be your problem.
Try manually tuning if your set allows. I've covered this in the posting linked to above.
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kaz: It could be that your mother has a Group C/D aerial which was the type usually installed in the days of four-channel analogue, particularly before digital came along during the previous decade.
Group C/D is the top third of the band of channels used for TV. 41, 42 and 44 (and 47[HD]) are in the middle band, which is Group B. PSB1 and PSB2 are on channels where B and C/D overlap.
Refer to this page for channel numbers of each Group:
Aerials, TV Aerial and Digital Aerial
(I haven't directed you to that page to read all the wordy explanation!)
Aerials are sensitive outside of their Groups to a degree. They don't receive "nothing" outside of group.
Further down that page is a graph with some gain curves. The green one is C/D and you can see that it slopes downwards. The gain is the sensitivity or the amount it can "hear" signals. This is just an example curve of one particular aerial to illustrate the point.
With this in mind, I suggest that you compare signal strengths of each UHF channel on the same device. Signal strength meters vary between receivers, so don't compare between different ones (only compare different multiplexes on the same receiver).
Digital reception requires the signal level to be above a threshold level. If it is, then it will work.
So it could be that the level of C44 is just below that which the receiver needs to show a picture. Depending on its design, it may indicate signal level when you manually tune. (Some receivers give more clues than others.)
Compare the levels of BBC One (C52) and ITV1 (C49) with those of the two COM channels you have which are ITV3 (C42) and Yesterday (C41). If the latter two are markedly lower then perhaps it is a C/D aerial.
If you can see that the tip of the aerial is green, then this indicates that it is a C/D one.
Do these checks with the receiver in question connected directly to the aerial socket (and not via the Sky box). If there is a wall socket with an aerial fly lead from that to the receiver, then try swapping it. Maybe you have one that you can try.
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Arnold Hague: I found the manual for it here:
http://www.sony.co.uk/sup…x653
However, it doesn't go into much detail about tuning.
If there is manual tune, then try manually tuning to the HD channel of your transmitter. HD services are broadcast using DVB-T2 standard whereas standard definition services use DVB-T. Therefore, there "may" be an option to select this when manually tuning.
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Pete: The Viera model may not have a HD tuner built-in. In the specification it will say that it is capable of receiving DVB-T2 signals (as well as DVB-T ones).
Freeview HD uses DVB-T2.
Earlier HD sets were HD Ready, meaning that they can show HD pictures, but don't have the means to receive them off the air.
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kaz: I had a look on Streetview at the road of the postcode associated with your postings.
I can see the distant horizon inbetween the bungalows to the east.
The Streetview photographs are dated April 2009, so they were before switchover and therefore pre-date the existance of the Bexhill transmitter, as it was only introduced at switchover.
At that location, the Bexhill and Hastings transmitters are in the same direction (to within one degree). Most of the bungalows on the right (as you enter the close) and some on the left and those at the end have their aerials vertical and directed at Hastings.
A terrain plot suggests that there is line of sight to the Hastings and Bexhill transmitters (so nothing in the way). Because I can see the horizon, I can well believe it.
jb38 has suggested that the aerial could be directed to Bexhill, which in view of the fact that it is has only been in service for a few weeks isn't likely.
So if the aerial is vertical and pointing at what might appear to be Bexhill, it is actually pointing at Hastings (owing to the fact that they are in the same direction).
The view in the direction of Heathfield doesn't look quite as good (I, of course, am only giving my opinion based on the Streetview photos). There are some trees behind the end bungalows that in the photos don't have any leaves on and these "could" be reducing the signal from Heathfield. Perhaps replacing the out of group aerial (if it is so) may make C44 available.
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Hilary: It's possible that the communal aerial system if fitted with a filter that only allows through (from the aerial) frequencies that are used by the transmitter. As the frequency used by COM6 has not been used before switchover, the system could require some adjustment.
Could you receive all Freeview channels before switchover? Did you get BBC One, BBC Two etc?
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Deeque: It depends on which transmitter is being received from!
There is a retune event scheduled for next May when ArqB (Yesterday etc) from Oliver's Mount will move from C61 to C49.
This is to clear channels 61 to 69 so the spectrum can be sold off to 4G operators.
D3&4 (ITV1, C4 etc) uses C60- which is obviously close, but I've no idea whether this might be a problem.
If you receive Tyne Tees from Bilsdale Moor, then the 4G services shouldn't affect it because it uses lower frequencies (and will continue to do so after it has switched).
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kaz, jb38: I eat my words!
The new Bexhill transmitter, which is located on the roof of the Hastings Direct building, is horizontally polarised and not vertically so as I assumed.
The downside is that it only carries Public Service (PSB) channels, so will probably only be used where a full service transmitter is not receiveable.
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Deeque: I have thought further about this.
Whilst the likelihood of interference obviously depends on the proximity to a 4G base station, it also depends on other factors such as sensitivity of equipment.
Another factor is how sensitive the receiving TV aerial is to the signal. For example, a TV aerial is most sensitive in the direction it faces and less so at the sides.
We can't know for certain where the mobile operators may choose to site their 4G base stations. However, in Scarborough, it would seem a pretty safe bet that one or more will wish to site their 4G base stations on the mast on Oliver's Mount, after all, it is visible at street level from most of the South side.
In such circumstances, TV aerials will be pointing in the direction of the 4G base station(s). Plus the TV aerials are vertically polarised (I assume that 4G will be vertically polarised). So I suppose that this will increase the likelihood of interference and I guess that this will be the case in other similar places where there is a local TV transmitter, as they often become a haven to the mobile operators due to the fact that they are sited on high ground.
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colin: I should imagine that the aerial system is the responsibility of the landlord.
I asked about reception of other channels before switchover, and in particular BBC channels, because they were at higher frequency on C59. ITV1 and ITV3 were low down on C24 and C27 respectively, so if you got these, then that suggests that the aerial system only allows channels through that are used.
After switchover, all channels except 54 were used before switchover.
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Barby: Maybe the signal is too strong and overwhelming your tuner:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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jb38: I see your point, although the satellite image shows quite a few trees, some of which could be a problem in the direction of Heathfield whereas in the direction of Bexhill it looks clear. So when you take into account the fact that it is a bungalow and therefore the aerial is lower than a house, would this not have some effect?
Also, one side of the close, which appears to be a little lower, is on Hastings and the other (slightly higher) is mainly on Heathfield. Some of those at the far (dead) end, which appears from the Streetview photographs to be a little higher than the rest, are on Hastings, presumably owing to the trees behind them.
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dave linden: This is because the transmitter on the top of South Cliff Tower is broadcasting on the same three frequencies as the Commercial channels from Hastings transmitter.
See Hastings transmitter | ukfree.tv - independent free digital TV advice
Unfortunately South Cliff Tower only transmits the Public Service channels, which are those that I expect you can still get from Hastings.
What the solution is may depend on exactly where you are.
If the interference from South Cliff Tower is strong, then you will have to accept that you aren't going to receive the Commercia channels from Hastings.
If it's weaker, you may be able to put your aerial somewhere where the interfering signal is blocked sufficiently.
In your general area, I believe that your only other alternative to investigate is receiving from Heathfield, although, again, it depends on where you are as to whether that might be a possibility.
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colin: I think that you should contact your landlord with a view to getting the aerial system adjusted. Everyone will be in the same boat, so others may be doing likewise.
I'm not sure what sort of aerial you will need. Whilst you are only two miles from the transmitter, you are very low down, being over 200m below the transmitter's antennas and as such I wonder if you could not have a good signal due to the umbrella effect - that is the best signal is way above you!
A look around at the aerials suggests that this could be the case as they seem to be large and some point at other transmitters.
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What about 5G, 6G etc; where are they going to go?
Or is the frequency plan to keep getting changed every five or ten years? That is, we make a plan and then in a few years time it is (partly) torn up and re-written and therefore many people incur additional expense and inconvenience.
At the end of the day, where a plan is made, it should be stuck to and not changed simply because we are unable to think any further ahead.
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Sticks: It could be that, having completed its automatic tuning scan, it decides to tune to the adjacent Honiton relay which only carries the three PSBs.
See here for the six multiplexes; each is carried on one signal:
DMOL Post-DSO Multiplex Channel Allocations
This page shows the three PSBs and three COMs.
The automatic tuning process scans UHF channels (frequencies) 21 to 69.
Due to the fact that Stockland's six multiplexes are on channel numbers are all in the 20s and Honiton's three PSBs are in the 40s, the aerial lead can be unplugged at about 30% of the scan.
Confirm by viewing the signal strength screen what each is tuned to:
PSB1 | BBC One | Stockland=C26 | Honiton=C42
PSB2 | ITV1 | Stockland=C23 | Honiton=C49
PSB3 | BBC One HD | Stockland=C29 | Honiton=C45
Check to see what each is tuned to and only perform a re-scan if one or more are tuned to Honiton. If they are all tuned to Stockland, then it isn't a tuning problem.
If you do scan and unplug the aerial after 30%, hold the plug away from the socket (not within a few inches) so as to avoid any possibility of the signal being transferred.
There is always the possibility that the signal from Honiton is so strong where your receiver is located that it could pick it up even without the aerial plugged in, so check that they are all tuned to Stockland. If this does happen, then you will have to see if there is somewhere else that you can take the receiver when there might be less Honiton signal, but where you will have access to an aerial connection. That, or if you can wipe it and manually tune to Stockland, although not all receivers allow this; they vary by design.
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Gordon Ormston: Where there are objects in the way, i.e. trees, different frequencies can be affected to differing degrees.
This can be an issue when placing a set-top aerial (inside, obviously!). You find the one channel might be good in one spot and vice versa in another an this is because the signal has travelled through objects like walls, i.e. it is because the path from the transmitter to aerial isn't so clear.
BBC One analogue was on C50. Of the other three analogue channels, only Channel 4 former C53 is now used for the BBCB (HD) multiplex. Did you have difficulty with reception of these? I suppose this isn't very scientific as you never received analogue on the other channels now used for digital so have nothing to compare to.
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KMJ,Derby: I'm thinking from the point of view of frequency planning. The plans keep getting changed and thereby force some to take action by changing their aerials in order to continue receiving TV.
The fact that there will be further generation mobile services in the future is surely a given. So where might they go? When might GSM be turned off, and therefore the frequencies thrown free for later generation services?
Am I right in understanding that the reason that the 800MHz frequencies are needed because 3G only uses the 2100 band and that this doesn't provide as good a service due to higher frequencies not travelling as well (walls attenuating signals etc)?
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Jim: The Commercial (COM) services, which include ITV4, don't have as wide a reach as the Public Service Broadcaster (PSB) ones.
The COMs transmit from 81 of the largest sites (largest by viewer population) and reach 90% of the population. There are over 1,000 small "filler-in" relays which carry only PSB channels because the COMs do not wish to invest in them. These cover 8.5% of the population.
The cost to the COMs to broadcast from these other sites is about the same as what it costs them for the ones they have now. As there objective is profit from selling advertising which they show to as many viewers as possible at lowest possible cost, then it's not surprising why they don't want to broadcast from the other sites. They don't have any "Public Service" obligation.
You've said that you reside in ST13 which is a big place and doesn't give any absolute indication of which transmitter you are receiving from. Indeed, provision of a full post code doesn't either, although it might narrow down the possibilities.
I do note that it is the area of Leek and that it has one of the PSB-only relay transmitters, so I wonder if you are receiving from it, hence why you are not picking up the COMs.
For a full list of services, see here:
DMOL Post-DSO Multiplex Channel Allocations
As shown, there are three PSB multiplexes (PSB3 is the HD one) and three COMs ones.
If you are using the Leek transmitter, then in order to see if you can ever receive the COMs terrestrial channels, then you need to investigate the possibility of receiving from one of the transmitters that carries them, such as Sutton Coldfield.
If you can't, then you will have to look at some other platform to receive additional channels. Freesat is a common alternative, particularly in areas where the Freeview COMs aren't available. There are some differences between full Freeview and Freesat. For example, Dave and Yesterday are not available on Freesat and this is probably because they are on Sky's subscription service. This does, of course, require a different box.
If you provide your location, preferably in the form of post code, we may be able to assess the likelihood/degree of difficulty you may have in trying to pick up the COMs.
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Richard: For information and a source for logs, see Aerials, TV Aerial and Digital Aerial
Rugeley transmitter only carries the Public Service Broadcaster (PSB) multiplexes. For a list of the six multiplexes, see:
DMOL Post-DSO Multiplex Channel Allocations
To receive the COMs as well, you will probably have to pick-up from Sutton Coldfield. You mention a secondary television; if the primary one is terrestrial, then why not use the existing aerial for both?
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
See the page on the mb21 Transmission Gallery for Rugeley:
mb21 - The Transmission Gallery
There is a comment on that page about an issue in the area with reflections of Sutton Coldfield's signals caused by the local power station's cooling towers. The relay itself uses a four-log array to receive from Sutton Coldfield for this reason.
Digital is more tolerable of reflections, so to what degree it will be an issue in your location, I don't know.
I'm not an aerial installer, but I understand that when you are talking such a low powered transmitter, line of sight is almost imperative.
Obviously the cooling towers aren't likely to be causing any reflections of the low powered signal from the school!
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Jack: A television which is described as HD Ready can display HD pictures, but does not have the means to receive the HD signals over the air. That means that it will require a separate HD receiver, whether this be a terrestrial one (Freeview) or a satellite one (e.g. Sky HD or Freesat HD). Click the words "HD Ready" for an explanation.
Only sets labelled as Freeview HD and/or with DVB-T2 in their specifications will receive HD as that is the standard that is used for it in this country. DVB-T is the standard used for standard definition terrestrial broadcasts, so a set capable of receiving standard and high definitions will have a DVB-T and DVB-T2 tuner in.
As for the question of getting all the Freeview channels, the UK has a two-tier terrestrial transmitter network. The biggest 81 transmitters carry the full service (they are the biggest by viewer population). There are over 1,000 small "filler-in" relays, including Newhaven, that carry only Public Service Broadcaster channels (PSBs).
The 81 full service ones carry both the PSBs and the Commercial multiplexes (COMs). This provides the COMs with coverage of 90% of the population. The cost to the Commercial broadcasters of transmitting from the 1,000 or so sites would roughly double their cost of transmission whilst only adding about 8.5% of the population to their potential viewer-bases. Because they operate on a profit making basis, by selling advertising which they show to as many viewers as possible which aquire at least possible cost, they aren't interested in transmitting from the small sites. The Commercial broadcasters have no "Public Service" obligation.
All transmitters broadcast the four HD services of BBC One HD, BBC HD, ITV1 HD and Channel 4 HD, as these are on a PSB multiplex.
For a list of services by multiplex, see here:
DMOL Post-DSO Multiplex Channel Allocations
That page shows the six multiplexes (each is a separate signal). All six are available from the 81 full service transmitters with the remaining being PSB-only.
Wideband aerials are needed in some cases because frequencies used by particular transmitters are spread out across the band and aren't all within the same portion used for the former analogue services.
Thus, in order to get the COMs, you will need to receive them from Heathfield or possibly Whitehawk Hill (adjacent to Brighton Racecourse) or Rowridge (on the Isle of Wight and is the main transmitter serving a portion of the south coast).
The predictor does not say what you "will" receive; it should be used merely as a guide. What you can receive depends on many factors and an on-site assessment can only really decide either way. Local obstructions such as buildings and trees can be an issue.
Whilst you don't have line of sight to Heathfield, owing to Beddingham Hill, it doesn't look to be too much of an issue.
I had a look on Streetview to see if there were any clues. I couldn't spot any aerials except for one on Glynn Road which is visible from your cul-de-sac. This one is pointing at Heathfield, so may give rise to the hope that you can receive from it.
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Sticks: Perhaps the poor HD mux on 29 from Stockland is why it decided to go with Honiton; i.e. the latter is the better of the two.
Whilst receiving from Honiton is a possibility, it will mean that you will then not have any of the COM services (see DMOL link I provided above).
However, as you are just less than four miles from the transmitter, I wonder if your receiver is being overwhelmed by signal and it is distorting, hence the poor quality (HD signals suffering from this before any other).
See here for an explanation and possible remedy:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
The COMs are at half power with respect to the PSBs from Stockland, so it is to be expected that if you do have too much signal that it will be one of the PSBs that will be affected.
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Jack: I take back what I said about the aerial I saw being on Heathfield. It is in fact on Rowridge, as is another on Glynn Road.
If you decide to try and receive from Rowridge, then I suggest that you use a Group A aerial and not a wideband yagi as their gain is lower on Group A channels, which is what Rowridge uses.
See here:
Rowridge Transmitter
Also, for best reception from Rowridge, have the aerial vertical rather than horizontal.
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Nick: Now that the transmitter is on full power, try turning your aerial to see if it is currently a little off-beam.
I know with my own experience with Emley Moor that the PSBs appear to be stronger. The aerial can be turned off-beam to the point where the COMs degrade but the PSBs are still strong and good quality. All six are at the same transmission power, so it must be the beam of the signal being put out that's different.
There are discrepancies between the number of people who are expected to receive PSBs+COMs as against those who will get PSBs only from transmitters that carry both at the same power:
The commercial multiplex after switchover: ArqA, ArqB and SDN | ukfree.tv - independent free digital TV advice
Like Emley Moor, Sudbury is one of those whose COMs are at the same power as PSBs. Maybe the beam of the COMs' signals aren't quite as high towards the horizon as the PSBs.
It is also worth pointing out that the higher the gain of an aerial, the narrower the angle of acceptance is, as gain is simply a trade-off of sensitivity in different directions. So the more "gain" you have facing forward, the more "loss" you have in other directions. Hence it could be more critical that it must be pointing exactly on target.
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Michael: Whether a box needs retuning when at a different location depends on whether it is the same transmitter that is being used because it is the transmitter's signals to which it tunes to that matters.
If your next door neighbour is using a different transmitter to you and you want to take your TV round to theirs, then you will have to retune.
If you are using a high power transmitter that covers a large area, you might go 100 miles to another location which receives from the same transmitter and hence won't need to retune.
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Sticks: The suggestion of trying an attenuator was to reduce the signal levels from Stockland, with a view to getting its HD watchable.
I suggest a 20dB variable one so it can be adjusted. Here is one such example (other sellers and outlets are available):
VARIABLE ATTENUATOR TV SIGNAL REDUCER 20dB 3 5 6 9 10 12 15 18 DIGITAL FREEVIEW | eBay
If you have a Group A aerial (red tip) for Stockland, then you should be aware that Honiton is Group B. See here for aerial groups:
Aerials, TV Aerial and Digital Aerial
However, group aerials don't receive nothing outside of group. You may argue that the Honiton signal is so strong due to the close proximity that it is OK, afterall, you have already picked up a strong signal from it with the aerial in opposite polarity...
See here for some gain curves which show sensitivities on different channels (these are just examples to illustrate a point):
Gain (curves), Again
You may find that even with what may be an out of group aerial for Honiton, it still picks up too much signal and needs attenuating.
As for tuning, I said to unplug the aerial at 30% to get Stockland and miss out Honiton. So if you start the scan with the aerial unplugged and plug in at 30% you should get Honiton and miss out Stockland.
Remember that the TV only stores channels it "sees" during the automatic tuning process. If you prevent it from "seeing" the ones you don't want, then it won't store them!
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Mik: The problem could be that, having carried out its scan of frequencies, the BT Vision box has decided to go with the signals from the Lyminge relay transmitter. This only carries the Public Service Broadcaster (PSB) services which are BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services.
See if you can find out whether this is the case or not. I'm not familiar with the BT Vision box, but usually receivers give the UHF channel number (frequency) that they are tuned to on the signal strength screen.
BBC One should be tuned to C50 (for Dover) and not C22 (Lyminge). Similarly, ITV1 should be C51 and not C25.
If either of these are not tuned to Dover, then run the automatic tuning scan with the aerial unplugged up until 40% of the scan. This will miss out scanning of the frequencies used by the unwanted transmitter.
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Nick: The PSBs from Sudbury and Rouncefall operate as a Single Frequency Network (SFN). This means that they use the same channels and therefore the aerial might pick up some signal from one transmitter and a bit from the other. So the result is the sum of the two at the point where the aerial is.
Rouncefall doesn't carry the COMs, so orienting an aerial based solely on the PSBs could lead to a not-so-accurate aiming of the aerial.
The only possibility I can think of is that the COMs are more restricted (than the PSBs), perhaps because to prevent interference on the Continent.
What strengths do you get on the PSBs from Sudbury?
If you can't get the Sudbury COMs, then in order to get Angia regional programming, you could perhaps have another aerial on Aldeburgh. The channels allow diplexing with Dover. Rouncefall is 39 degrees clockwise of Dover, so this is probably too far off beam for the aerial you have to pick it up.
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Malcolm Wood: If you're reading this, I've just read the article you provided a link to written by Bill Wright about phased arrays. Have you tried it out and are you in business?
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kaz: The downside to using Hastings is that the three COM channels (from Heathfield these 42, 44 and 41) are on the same channels as used by the transmitter in Eastbourne on the South Cliff Tower which, like Bexhill, is PSB only. So it may be the case that these are now wiped out, or at least intermittant at your mother's location.
Getting the desired sub-regional BBC and ITV is possible when picking up from Hastings, albeit starting to get more costly. A second aerial could be installed on Bexhill with diplexer (which combines signals from the two). It is unfortunate that Bexhill is horizontal as a single aerial would have worked for both otherwise (because they're in the same direction). As I say though, this is getting costly with the extra aerial and diplexer, and is not forced to work, what with the Eastbourne PSB transmitter being co-channel with Hastings' COMs.
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What was observed with the channels being available one day and not on another is what can happen with digital reception. It may be that when these services were picked-up, the signal level was "just" above (or a "bit" above) the threshold required (by the receiver) and that now it is "just" below that threshold. The difference in levels between the two may be small, but the effect is stark (which is digital reception for you).
Signal levels vary all the time due to the weather etc. Had the level been "quite a lot" above the threshold, a reduction of the level experienced could have still left it above the threshold and therefore it would have continued to work and your mother would have noticed nothing.
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Steven Moore: You have posted on the page for the Torquay Town transmitter, yet C57 is that of its parent, Beacon Hill.
If your aerial is vertical and points to Torquay Town transmitter which is on the roof of Walden Point on St Luke's Road South then the problem is that your box is incorrectly tuned.
If your aerial is horizontal and points to Beacon Hill, then perhaps you have too much signal. See this page for an explanation and remedy in this case:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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kaz: Following on from what I said about the signal level dropping just below that needed, it does make me wonder whether a signal booster may improve matters. Signal boosters aren't the be all and end all and can have a negative outcome depending on the circumstances.
jb38, as the expert, perhaps you can advise as to whether a signal booster may be worthwhile here, particularly if a replacement aerial for Heathfield is not likely.
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Jarzembowski: There are two transmitters that are not far off being in line with one another from your location. As such, I suggest that the most likely answer here is that your receiver has tuned to the wrong one.
The two transmitters are (along with UHF channel numbers):
Whitehawk Hill @ 283 degrees (adjacent to Brighton Racecourse)
PSB1 (BBC One etc) C60
PSB2 (ITV1 etc) C53
PSB3 (BBC One HD etc) C51 (if applicable)
COM4 (ITV3 etc) C57
COM5 (Pick TV etc) C56
COM6 (Yesterday etc) C48
Newhaven @ 264 degrees (Harbour Heights on the west side of the Ouse)
PSB1 C50
PSB2 C43
PSB3 C40
Based on what you've said, there are two things that make me think that your aerial is directed at Whitehawk and not Newhaven (albeit that there is just 20 degrees difference):
- Only Whitehawk carried Freeview before switchover, so if you were receiving it then, that is the transmitter you were using.
- Newhaven only carries PSB services now (see above). Thus if COM channels are being received, they must be from Whitehawk. You have only identified PSBs as being a source of poor reception.
Bring up the signal strength screen whilst on BBC One and it should tell you that it is tuned to C50 (Newhaven) or C60 (Whitehawk). I suspect that it is tuned to Newhaven instead of Whitehawk for PSBs.
How you solve this problem depends on how well designed your receiver is. If it has manual tuning, then this will be much easier to accomplish.
During the automatic tuning procedure it scans UHF channel numbers (frequencies) 21 to 69. Have the aerial unplugged up until it is passed those channels used by Newhaven. Plug the aerial in when it gets to 61% which should coincide for about C51 (so just after Newhaven highest channel). The scan may go fast with the aerial unplugged.
Once you've done this, then go to manual tune and tune to UHF channel 48 to add COM6. You will probably need to do the same for PSB3 which is on C51, if your receiver is a HD one. You may find that ITV1 is missing, in which case also do a manual tune on C53.
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Martin: As geoff says, check that it is tuned to Whitehawk and not Rowridge.
If it is, then the simple workaround is to unplug the aerial for the first 40% of the scan. This will miss out low channels (frequencies) used by Rowridge, but will scan higher ones used by Whitehawk.
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Martin: If you do find that it is tuned to Whitehawk, then I suggest that you get a 20dB variable attenuator.
For example (other outlets and sellers are available):
VARIABLE ATTENUATOR TV SIGNAL REDUCER 20dB 3 5 6 9 10 12 15 18 DIGITAL FREEVIEW | eBay
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Nick: I wonder if there is a notch in the Sudbury COMs antenna in your direction. Hence you aren't getting the full benefit of the 100kW. I think this because you said that you could get the 14kW signals occasionally.
Thus, maybe the strength of those signals is significantly weaker than the PSBs and this is contributing to desensitise your receiver which is in turn making it insensitive to the COMs.
With this in mind, I wonder if you need to boost the strength of the COMs only. A spectrum analyser would obviously show you instantly if they are there, but weaker than the PSBs.
Before trying what I've outlined below, you could perhaps try attenuating the signal to see whether the strength of the COMs increases, even if not enough to put it above the threshold to give you a picture.
This may or may not work as you will obviously be reducing all signals and not just the PSBs.
Or: If you were to use a Group C/D bandpass filter, this would remove all but C/D channels and hence remove the PSBs. You could then experiment by seeing what can be picked up. Then try amplifying it.
Obviously, as KMJ,Derby says, the siting of the aerial may be a factor. With little or no signal it is difficult to know whether the aerial is being aimed in the right direction. Remember that the PSBs are a Single Frequency Network with Rouncefall, so going by those signals may be a red herring.
If you successfully get the COMs from Sudbury, having amplified them (and them only), then you need to diplex the output of the amplifier with another feed containing the PSBs, either from Sudbury or Aldeburgh. Your former analogue Group B aerial may be of use here if you decide to receive PSBs from Sudbury.
Bear in mind that in the future, additional COMs may come on the air using channels between 31 and 37 and likely as not using the same or similar quasi-national network. So you may have to change again if you want to pick them up. How you do it now may affect how easy any future change might be.
A diplexer which splits at C51 will allow you to have the output of the amplifier (whose input is filtered to allow C/D only) *and* either Sudbury or Aldeburgh PSBs (which needn't be filtered) going to your receiver.
I assume that the C/D filter on the input of the amplifier might be needed to prevent any nasty effects by boosting the PSBs (even though they will be subsequently filtered by the diplexer.
As I might have said before, I'm not a professional and am just putting my thoughts forward based on what I understand. I would appreciate comments by the professionals on what I've proposed and how likely they think this might be an effective solution.
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The message at the top of this page does say that Sudbury is "liable to interruption" which does suggest that engineering work is ongoing. Maybe it will be worth waiting to see if reception of the COMs is possible on completion before adjusting your aerial arrangement.
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Alan Murray: Yes, Freeview HD is operated by the Public Service Broadcasters and is therefore available from all transmitters.
It is the Commercial services that don't have as good a coverage, as you already know and this is because they have no "Public Service" obligation.
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Andy: See postings by Nick immediately above yours. He is a stone's throw from you off Woodbridge Walk and says that in his area only Public Service channels can be received.
See the terrain plot from the Sudbury transmitter to your approximate location:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
As you can see, the path of the signal runs close to the ground for quite a few miles. Obviously there are objects on the ground, so it is not surprising that reception isn't good.
Imagine if the transmitter was sending out a beam of light, then consider trees and buildings that are likely to be in the way.
See here for the full list of Freeview services:
DMOL Post-DSO Multiplex Channel Allocations
The PSB multiplexes are the Public Service Broadcaster ones. The COMs are the Commercial ones which have limited coverage with respect to the PSBs. Nick has been unable to receive the COMs from Sudbury.
Based his comments, I get the feeling that you may well be limited to Public Service channels. Or the COMs may be intermittent. Which channels are causing problems (PSBs, COMs or both)? Does each caravan have its own aerial?
Digital UK predictor considers Sudbury to be "marginal" at your location, and likewise Aldeburgh. The latter is PSB-only.
The predictor should be regarded as a guide. Local obstructions such as trees and buildings aren't taken into account. It may be a clue as to likelihood of success of reception.
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Janine Hindmarsh: Shotleyfield does not broadcast Freeview yet; it currently only carries the four analogue channels.
If their aerial is directed to the Shotleyfield transmitter it will be vertical. If they have been receiving Freeview with it, then they have been lucky!
There is engineering works ongoing at the various transmitters in preparation for switchover. Perhaps this is the cause of the (perhaps) slight change in signal which has resulted in them being unable to pick it up.
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As a PS:
After switchover, Shotleyfield will broadcast only 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.
The transmitters that broadcast Freeview before switchover will carry the full range of channels after switchover. In that general area these are Pontop Pike and Fenham.
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Pippo: See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Janine Hindmarsh: I have had more of a look at this.
In a valley, which transmitter(s) can and cannot be received from can vary house by house. So my comments are general.
From what I can see, Pontop Pike is the only likely Freeview transmitter that "may" be received in the general area of your parents. With this in mind, they must have been receiving Freeview with the aerial facing another way and of opposite polarisation (aerial vertical whereas signal is horizontal).
This perhaps suggests (I remind you that I can only be general) that the signal is strong and that reliable reception from Pontop Pike "may" be possible with an appropriate aerial aligned correctly.
If they continue with their aerial directed to Shotleyfield, then until switchover, intermittent reception of all channels is possible (due to them being picked up from Pontop Pike).
Come switchover, as Shotleyfield will only carry the Public Service channels, then they will be expected to be OK as the aerial faces the transmitter. Because it won't carry the Commercial channels (ITV3, Pick TV, Film4, Dave etc), then should the receiver pick them up, which it may do, then they can only possibly come from Pontop Pike, so reception may be poor, intermittent or non-existant (a bit like now).
For this reason, they may decide (or you might think it a good idea to advise them) that they have an aerial on Pontop Pike now. I remind you that what I've written is general, and it is also the case that an assessment of whether reliable reception from Pontop Pike is possible can only be made by an installer on site.
The Commercial channels have limited coverage which is about 90% of the population, whereas the Public Service channels serve everywhere that the current analogue does. In some cases, reception may be possible from another transmitter that carries the Commercial channels.
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Dee: Based on the fact that you are only 9 miles from the transmitter, the problem may be too much signal. See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Nick: When a receiver goes through its automatic tuning process, it scans all channels. Having done this it then has to "decide" which of the channels it is to go with, where duplicates are found.
In this case it is going with those from Aldeburgh. This is obviously not the desired result.
The solution is to unplug the aerial for the first 30% of the scan so that it doesn't get the chance to "see" the Aldeburgh channels.
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david C: The predictor thinks that Tacolneston may be more reliable at your location.
Due to this, confirm that your receiver is tuned to Sudbury for all channels, and not to Tacolneston for some.
This information (UHF channel/frequency that it is tuned to) is usually given on the signal strength screen.
PSB1 | BBC One | Sudbury=C44 | Tacolneston=C55
PSB2 | ITV1 | Sudbury=C41 | Tacolneston=C59
PSB3 | BBC One HD | Sudbury=C47 | Tacolneston=C62
COM4 | ITV3 | Sudbury=C58 | Tacolneston=C42
COM5 | Pick TV | Sudbury=C60 | Tacolneston=C45
COM6 | Yesterday | Sudbury=C56 | Tacolneston=C50
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Nick: I sympathise with your predicament.
The Commercial broadcasters were not mandated by law to follow the same coverage as the Public Service Broadcasters. This can only come back to politics rather any deficiencies in the engineering of the network. They follow the laws of capitalism which means that if it isn't worth it then it doesn't get done. They operate to provide them with a return.
After switchover, the Commercial broadcasters use less error correction so as to give them more space to fit in more services. This means that the signals are less robust than the PSB ones.
See the newsletter about the retune last November:
http://www.digitaluk.co.u….pdf
It says that on 27th June 2012 SDN would adopt 8k mode, but it makes no mention of this for ArqA and ArqB, so perhaps they were already in 8k mode (with the less error correction).
Nick, you did say that you could get ITV3 better when it was at 14kW, and it is carried on SDN which was in 2k mode then (and presumably more error correction than now). So the change in error correction could perhaps be the dampner, irrespective of power increase.
When you consider that the signal path to Hollesley runs low to the ground for miles, then perhaps this explains why the less robust COMs aren't available. That is, they are getting "bashed about" too much.
In which case, it would seem logical to suggest that the amplification of only the COMs I suggested above may NOT do the trick because the problem is more likely to be poor quality signal (for which amplification won't solve).
This leads me on to wonder if you would be better off with a lower gain aerial and amplifier. The objective being to get a better quality signal due to the wider acceptance angle. Obviously a lower gain aerial gives less signal strength, which is why an amp is necessary. I have seen this suggested as being an improvement on a high gain aerial in cases such as at the bottom of a hill, perhaps lined with trees. Perhaps the professionals could comment how likely this might help Nick.
It is, of course, always a possibility that reception may be variable owing to rain, leaves on the trees and so on.
Your other possibility is to diplex your aerial on Dover for the COMs with one on Sudbury or Aldeburgh for the PSBs. Obviously Dover may also be subject to variable reception. Its SDN and ArqA are co-channel with two of Tacolneston's PSBs. Your aerial will also be facing the Continent which could increase your chances of suffering under lift conditions. Also, the fact that the signal isn't strong due to your distance probably means that it is more susceptible to being knocked out due to interference from other stations that are co-channel under certain conditions.
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Nick: Of course, as you say, the best thing is to wait until the reported engineering work at Sudbury is completed to see what you have then.
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Dave Whetstone: There is no further retune required for Over Norton. There was a retune affecting Suffolk, Essex and Kent so maybe the messages relate to that.
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Nick: Which platforms TV channels choose to go on is up to them.
Challenge, Dave, Pick TV and Yesterday make themselves available on the Sky subscription service and via the Freeview Commercial multiplexes. These are decisions which they believe are better financially for them. Presumably they consider that the cost to be on Freesat is not as beneficial as being on Sky. Similarly, the outlay they make to be a on Commercial Freeview is better for them than not being on it.
Challenge and Pick TV are owned by BSkyB, so it isn't surprising that they don't make themselves available via satellite services that are in competition with Sky.
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Nick: This site is independent. The channel numbers above have not been updated since the changes which took place on 27th June.
Briantist: Can you update the channel numbers and powers following these changes?
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Nick: See Why do the six Freeview "multiplexes" have twenty different names? | ukfree.tv - independent free digital TV advice
Use the Digital UK site to find out channel numbers (tick the "Detailed view" box):
Digital UK - Postcode checker
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Nick: I said that your box tunes itself to Aldeburgh because in your posting at 10:12AM today, you said "my box tunes itself to stations from ch23, Aldeburgh".
You said subsequently in your posting at 12:12PM that your Aldeburgh aerial has an amplifier but the Sudbury one doesn't. Are these diplexed together or are they fed separately into your lounge (allowing you to connect to either but not both) or have you "combined" the feeds in some other way?
If the Aldeburgh aerial is connected, then just turn off the power to the amp, leave the aerial in during all of the scan. Turning off the power to the amp will mean that no signal will come out of it.
Or, if you still need to make your receiver avoid Aldeburgh during its scan, plug the aerial in when it gets to 30%. Some devices are more helpful than others, so obviously I can only be general. If it gives percentage progress, then 30% of the scan (which runs from 21 to 69) is about C35. If it gives no percentage and no UHF channel number and is simply a bar the goes across the screen, then you will have to guess or improvise. For example, can you hold a ruler up to the screen and measure the bar and hence work out roughly where the target point is for plugging in the aerial?
The target area is from 15% to 40% so there is quite a big area to aim for. I have calculated these on the basis of the highest channel from Aldeburgh and the lowest from Sudbury. If it has manual tuning, then use it to add any that are missing, if you get the aerial in a bit too late.
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Paul: See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Nick: It may be that you will have to trial PSB reception from each transmitter to work out which is best. With digital reception, variable or poor reception may only become apparent at certain times, e.g. momentary freezing may be intermittent. The automatic tuning process is unlikely to be able to make this decision for you.
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Nick: If a receiver gives information as to what channel/frequency it is tuned to, then this is usually given on the signal strength screen. A few don't, so there is little way of knowing, particularly if two possible transmitters broadcast the same regional programming.
Not giving this information is poor design in my opinion and it is not confined to "cheapo" devices. I came across a Sony RDR-HXD860 which gives no clue as to which UHF channel it is tuned to. I have a RDR-HXD870, which I believe superceeded it and that does give the channel number on the strength screen.
Some use frequencies instead of chanel numbers and C28 is 530.0MHz and C41 is 634.0MHz.
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Nick: I'm not familiar satellite receivers as I've never used one. However, I have read that "Freesat" branded set-top boxes will automatically tune in all services that are part of the Freesat offering. Other free-to-air channels can, I understand, be added manually. Presumably this is where manual tuning is available (I have no idea whether some devices are more restrictive than others, as is the case with terrestrial receivers).
See here:
List of free-to-air channels at 28°E - Wikipedia, the free encyclopedia
Obviously this Wikipedia page is not forced to be up-to-date or correct.
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Nick: The full list of Freeview services by multiplex are here (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
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Nick: Sudbury has had to wait for Dover to switch-over so as to throw free the three final COMs channels. A few other transmitters have had to go through similar "temporary" stages, although at a year, this is one of the longer ones.
See the DMOL link I provided as it lists services by multiplex which are identified as either "PSB" or "COM".
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Nick: For Sudbury, a Group E aerial is semi-wideband as it spans Group B and Group C/D channels.
The other alternative is to use a Group C/D aerial for the COMs and diplex it with a Group B for the PSBs. Or the wideband may be suitable for the PSBs with it being diplexed with a C/D to pick up the COMs.
For diplexers, see Online TV Splitters, Amps & Diplexers sales
The one that "splits" at C51 should be suitable if the two-aerial approach is to be employed.
As I say, I'm not a professional so I don't know under what circumstances that may be better than a single Group E aerial.
Clearly the diplexer acts as a filter so on the COMs channels only the C/D aerial is used, and on the lower PSB channels only the other aerial is used.
See also:
Sudbury Transmitter
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Nick: I used Megalithia to plot the terrain between Hollesley and Dover transmitter and I reckon that you may have line of sight at 66 miles.
I am not so sure that the same is true of the location which is further north and closer to Aldeburgh.
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Sticks: It could be water in the cable.
HD from Stockland is on C29 which is what Channel 4 analogue used to use. Did you have any issues with reception of that channel?
The only other observation I can make is that despite being so close to the transmitter, you don't have line of sight to it.
The terrain drops down and there are two brows over which the signal is having to go to get to you:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
These correspond approxiamately to the areas of around about St Michael's Church and Manor House School and both of these areas have trees. So on the brow of those "hills" (shown in the terrain plot above) it would appear that there are objects (trees).
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Sticks: I have just noticed that there is a message at the top of this page about engineering works at Stockland Hill and the possibility of it being "liable to interruption".
I would ask, has this always been an issue? But if it has been tuned to Honiton for HD all along, then results may be poor or intermittent.
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Sticks: About possible water in the cable, check for damage to the insulation, such as chafing on a roof tile IF you can work safely at heights and have the appropriate ladders and knowledge to do so.
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Susan: The Commercial (COM) services changed channels from Sudbury last Wednesday.
See this page for a full list of services by multiplex (those that have a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
A multiplex is a single signal.
Try attempting manual tuning for missing multiplexes, if your receiver allows:
COM4 | ITV3 | C58
COM5 | Pick TV | C60
COM6 | Yesterday | C56
Failing that, perhaps your aerial needs replacing. See the posting I to Katharine immediately above yours in which I linked to another posting of mine which explains.
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Nick: For which channels are PSB (and which are COM), see the "DMOL" link I provided in my posting at 1:48PM.
Also see this page, particularly starting at the heading "Independent Television Commission: 1, 2, A, B, C and D":
Why do the six Freeview "multiplexes" have twenty different names? | ukfree.tv - independent free digital TV advice
For more general information on what Public Service Broadcasting is, type into a search engine something like {uk public service broadcasting}.
Basically, as explained in the link above, BBC, Channel 3 (branded "ITV1" by ITV Plc in England), Channel 4 and Channel 5 are Public Service Broadcasters and as such have obligations placed upon them. This includes achieving a particular level of coverage and which means the installations of small relay transmitters in populated areas that aren't otherwise served.
The PSB1 multiplex is for exclusive use of the BBC. PSB2 is licensed to D3&4 which is collectively owned by Channel 3 licencees and Channel 4. This multiplex must carry ITV1 (or STV in parts of Scotland and UTV in Northern Ireland), Channel 4 and Channel 5. The Public Service broadcasters can decide which other of their sister services they wish to carry on their PSB multiplexes.
You're now going to ask, why have they included ITV1+1 on PSB2 instead of ITV3? I imagine that the answer is down to the return they expect from the advertisers. Presumably providing an ITV1 one hour behind is seen as being more lucrative than ITV3. So it is all down to money and only ITV1, Channel 4 and Channel 5 must be carried on PSB2.
PSB3 is the only HD one, and whilst licensed to the BBC also carries HD services on behalf of ITV1 and Channel 4.
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I am not sure that Aldeburgh 23 and Sudbury 41 are classed as different "networks" or "regions".
Aldeburgh is a relay of Tacolneston. According to this site, both Tacolneston and Sudbury carry BBC East and ITV Anglia East. I would be interested to know whether, as far as the receiver is concerned that these are the same network/region.
Sandy Heath is the third Anglia transmitter and it carries "ITV Anglia West". So there appear to be two variants of ITV Anglia; "East" broadcasts from Tacolneston and Sudbury and "West" comes from Sandy Heath. Do you know different?
I receive from Emley Moor, but I'm in a location where I can usually pick up Belmont up off the back of the aerial.
Emley Moor and Belmont are part of different BBC and ITV1 sub-regions. When I run the automatic tuning function on my Sony RDR-HXD870 is removes 80-odd duplicates once it completes. This leaves me with all services from Emley Moor plus the BBC One and ITV1 from Belmont. So I end up with two BBC Ones and two ITV1s but not two of everything else.
On another TV, I have all the duplicates, with the highest logical channel number (LCN) being 937! So it would appear that how it works depends on the design of the set.
Freeview TVs usually store duplicates starting at LCN 800.
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D Green: Unfortunately not; the Commercial (COM) multiplexes do not have as wide a coverage as the Public Service Broadcaster (PSB) ones. The main reason being that the small transmitters like Rye don't carry them because the operators don't regard it as worthwhile to pay for them.
The UK now has a two-tier terrestrial transmitter network. 81 of the largest transmitters (largest by viewer population) carry all six multiplexes (three PSBs plus three COMs) and these serve around 90% of the population. (A multiplex is a single signal that carries multiple "services".)
The other 1,000 or so small "filler-in" relays like Rye carry only PSBs and serve about 8.5% of the population.
The reason for this is because the Commercial broadcasters operate for profit only and have no "Public Service" obligation. They were invited to increase their coverage and declined. For them to transmit from the 1,000 relays would roughly double their cost of transmission. As they are interested in getting as many viewers as possible at lowest possible cost (to show advertising to), then it's not surprising that they've stuck with the biggest transmitters.
Reception from Dover may be possible. I had a look down your road on Streetview and all the aerials I could see were on Dover. So you may be lucky and be able to receive the full complement of channels from Dover.
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Jackie K: It could be the communal aerial system that needs adjustment.
They are sometimes filtered so as to only "let through" (from the aerial) frequencies used by the desired transmitter.
There are six frequencies (each known as a multiplex) for Freeview which each carry a number of services and those you mention are on the same multiplex (and therefore same frequency). This multiplex uses a frequency which wasn't used by Bluebell Hill before switchover. The other five use frequencies that were used before switchover (either for analogue or digital).
So maybe the aerial system needs adjusting for this new frequency.
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John Hearnshaw: Unfortunately 4seven won't be available from the Calver Peak transmitter because it is carried on one of the Commercial multiplexes which don't broadcast from there.
It will be available on Freesat:
What's new? - freesat
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Mike Summers: With the except of Heathfield, the other three possible transmitters at your aunt's location are within 22 degrees of one another and all broadcast vertically. Hence her receiver could easily be pickup up the wrong one.
At 274 degrees is the Newhaven relay which only broadcasts Public Service channels and did not carry Freeview before switchover.
At 284 degrees is Whitehawk Hill which is adjacent to Brighton Racecourse and carries all Freeview channels and had low power Freeview signals before switchover.
At 262 degrees is Rowridge on the Isle of Wight which serves a large chunk of the south coast. It was horizontally polarised only before switchover and now transmits horizontally and vertically.
If your aunt's aerial is vertical and pointing at Whitehawk or Newhaven, it could be picking up Rowridge a bit now, seen as it broadcasts vertically.
I had a look down the road and I see that they are bungalows and therefore are lower down, so it might explain the need for amplifier. A few aerials are horizontal and thus on Rowridge. Others are vertical and could therefore be on Newhaven or Whitehawk.
If you're tuning the TV, then connect it straight to the aerial to tune it(via the power supply for the amp). That way you know that the DVD can't be causing any problem.
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cjh: It may be the case that Buckland (known as "Dover Town") is a better signal for you, which is why the aerial is directed to it.
In the days of four-channel analogue, all transmitters carried the same four channels. Main high power transmitters like those at Hougham (known as "Dover") cover large areas. Unfortunately their signals don't get everywhere, primarily owing to the terrain.
Because the ground slopes downwards towards the sea, reception from Dover is difficult to impossible, which is why the small "filler-in" relay transmitter at Buckland was installed. This is sited in a location where it can receive from Dover and where it can be "seen" by the area that has difficulty receiving from that main station and this is so that the area can receive from it.
It carried all four analogue channels and was therefore not inferior to the service offered by Dover.
Post switchover there is a two-tier terrestrial transmitter network. There are two types of broadcaster: Public Service ("PSB") and Commercial ("COM").
The four analogue channels had and still have a "Public Service" obligation (as does Channel 5) and they are now carried from all transmitters that carried four-channel analogue in the past, as this includes Dover Town.
However, the COMs don't have a "Public Service" obligation. They operate solely for their own benefit; i.e. to turn a profit. They transmit from 81 of the largest transmitters (largest by viewer population) and this includes Dover. This gives them coverage of 90% of the population.
They were asked if they wished to increase their coverage and they declined. For them to transmit from the 1,000 or so small relays like Dover Town would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer-bases.
When their objective is to get as many viewers as possible at lowest possible cost to show them advertising (which they sell), it's not hard to see why they don't wish to invest in the relays.
As Mark Fletcher says, a more specific location is necessary. Looking at the contour lines in the CT17 area, likelihood/difficulty of reception from the main Dover transmitter is likely to vary greatly owing to the slope.
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Cherry White: Tay Bridge does not broadcast ITV4 or any of the Commercial channels, thus he is not receiving them from it. He is probably picking up from a different direction to which his aerial faces and is therefore "lucky" to get any signal.
Different receivers have differing sensitivities, so some may get and some may not when the signal level is borderline.
It "may" be the case that if he had an aerial directed to the transmitter which he is receiving it from that the signal level would be much improved and therefore would be available on all of his receivers. It would also reduce the likelihood of intermittent reception which could ensue because he is using his aerial to receive a signal which it was not installed for.
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Cherry White: As Mark says, an idea of your location may allow us to gauge as to how likely you might be to receive from a transmitter that carries all Freeview channels. Tay Bridge does not and will never carry all channels.
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Nick: I used Megalithia to plot the terrain between you and Dover:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
The curvature of the Earth would appear to be exagerated which is what I've experienced with Megalithia before over such long distances. What I did then was click the link below the plot to view the map between the two points.
I then found the co-ordinates for the point on the Kent coast where the signal path line intersects; this is at Birchington.
A plot from Dover to this point shows that there is clear line of sight:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Unless there is any obstruction between your house and the coast, then this would appear to suggest that you do have line of sight to the top of the Dover mast.
The curvature of the Earth is said to be 8 inches per mile. This works out as 13.4 metres over the 66 miles.
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Stan: This is correct; Alexandra Palace only carries Public Service Broadcaster (PSB) multiplexes. It does not carry the Commercial (COM) ones which carry Russia Today, Al Jazeera, ITV3, Pick TV, Dave, Film 4 and others.
For a full list of Freeview services, see here (those with a bullet in the "E"/England column apply):
DMOL Post-DSO Multiplex Channel Allocations
There are three PSB multiplexes and three COM multiplexes. Each multiplex is carried as a single signal. PSB3 is the HD one.
Your current aerial may not be the best for Alexandra Palace, as it may be a Group A design (red tip). If it is a wideband, then it will be suitable. A wideband isn't needed for Ally Pally; a C/D aerial will work.
For information about aerial groups, see:
Aerials, TV Aerial and Digital Aerial
If you are considering realigning your aerial because you're having reception issues from Crystal Palace, then you may now be considering replacement of the aerial (still on Crystal Palace so as to get all channels). See this page for guidance and information about aerials for Crystal Palace:
Crystal Palace Transmitter
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Nick: The horizon is where the ground or sea "meets" the sky. There can be things on the horizon which are effectively "protruding" from the horizon.
Imagine if, after having gone over the horizon, the ship were to sprout a tall mast and fly a flag on it. The height of the flag may be visible over the horizon, even though the ship itself is not visible owing to the curvature of the earth.
The same appears to be true of the top of the Dover mast. Whilst it may not be possible to see it due the air not being clear, there is no land (hill) or other object inbetween it and you when on the top of your house.
It could be that the Kent coastline, and even the high ground on which the transmitter sits, is over the horizon (from your vantage point), but the top of the mast is not.
Visible light is also carried as electromagnetic waves. If you're driving your car at night you have the headlights on and they shine into the distance and on to objects which reflects the light back to you.
The more the mist and fog set in, the more difficult it is to see the objects. Headlights in dense fog result in illuminating the water droplets. The light becomes much more of a "ball" in front of you than a beam shining afar.
Conversely, other drivers see nothing of the radiated light until they are close. This is because the light is no longer travelling as far as it does when visibility is clear.
And so, I imagine that TV reception is much the same. The almost sudden loss of signal is probably down to a sudden mist moving in. The signal is travelling over the sea for over 40 miles.
Imagine what it would be like to look out from the top of the transmitter and see the signal being radiated. On a clear day, the signal will travel and objects a long way away will be visible in the "light" of the signal. When the mist comes in, the electromatnetic energy will end up getting "caught" in the droplets. What will be seen is the "light" reflecting back from the droplets. Those who can normally receive the signal will find that they get nothing or much less "light" than they normally do.
This suggests that you may not have stable reception of the COMs from Dover after all. You may have to listen to the Shipping Forecast to find out whether your viewing may be affected.
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John Mason: 4seven is not available before switchover due to insufficient capacity.
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Linda Dale: If you only have Freeview Light, then no, you won't get 4seven; it is available on Freesat though.
The Digital UK predictor suggests that reception of all channels from The Wrekin "may" be a possibility. What can and can't be picked up may vary by house. Trees in the way could prevent reception from a particular transmitter. The predictor should be treated as a guide; only an installer on-site can say what can and can't be received.
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John Clark: According to Digital UK and Ofcom, C42 is on the lowest power of the digital channels from Bilsdale at 1.6kW. All the rest are 6kW except for C34 which is at 4.8kW.
As Mark says, C42 is the only out of group one at present, if you are using a Group A aerial.
See:
Aerials, TV Aerial and Digital Aerial
Bilsdale TV Transmitter
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John F: Err, no. It's down to the laws of capitalism and it is explained above !!!
The Commercial broadcasters selected the most lucrative transmitters (those with most viewers).
The rest cover 8.5% of the population and the cost to run them is about equal to the cost of the 81 they have which cover 90% of the population.
As they are profit making organisations, showing advertising to as many viewers as possible which they aquire at lowest possible cost, then it's not surprising that they aren't interested.
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John Marsh: Is it a "Freeview HD" TV which has a DVB-T2 tuner in? What is it's model?
"Full HD" simply means that it goes up to the "full" resolution of 1080p and does not add any qualification to the ability to receive HD broadcasts off the air.
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Sticks: Good to hear you got it sorted, that's quite an increase!
Perhaps your aerial was in a shadow.
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Clare: Is your aerial directed to Beacon Hill which overlooks Torbay or Stockland Hill?
Confirm that it is tuned correctly. If you have difficulty with it picking up the wrong one, then:
- for Stockland, run the automatic tuning scan and unplug the aerial at 30% or when it gets to C30; or
- if your aerial faces Beacon Hill, start the scan off with the aerial unplugged and plug in when it gets to 30% or C30.
If it is Beacon Hill, then C60 is used by BBC and is also used by Cherbourg which is about 45 miles across the Channel. Cherboug does not share any other channels with Beacon Hill.
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Terri: Your postcode resolves to an appartment block and these usually have communal aerials.
If you are using a communal aerial, then it may need to be adjusted. See this posting from Hilary who has the same problem and see my response to her:
My Freeview box has no EPG, is blank on FIVE, ITV3, ITV4, ITV2+1, has no sound or the channel line up is wrong | ukfree.tv - 10 years of independent, free digital TV advice
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John: Perhaps your receiver is tuning to the Seagry Court transmitter for BBC standard definition which is on UHF channel 41. It should be tuned to Mendip on C61.
Carrying out a retune should only be done in order to tune the receiver differently to what it already is. Have you established whether this is the case or not?
As Einstein said, insanity is doing the same thing over and over again and expecting different results.
If your receiver is picking up BBC from Seagry Court, then it's unlikely that this would change, irrespective of how many times you try.
The signal strength screen should tell you whether BBC One is tuned to C41 or C61. If it is tuned to Seagry Court, then run the automatic tuning scan through with the aerial unplugged up until 55% or C48. This will miss out scanning of its channels. Then go to the manual tuning function and tune to C48 for ITV3 and associated services. If Yesterday is missing, manually tune to C52 and if ITV1 is missing, manually tune to C54.
These manual tunes are necessary due to possible inaccuracy in getting the aerial lead back in. The highest frequency used by Seagry Court is next to the lowest of Mendip (which is C48).
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John Slater: What do you distribute (or what did you distribute) using the LoftBox?
The references to distributing HD means that if you have a HD box in one room, you cannot carry the high definition picture to another room using the LoftBox. These does not preclude the reception of Freeview HD in every room using a local receiver (e.g. set-top box or HD TV with built-in Freeview HD receiver).
The purpose of LoftBox is to carry different signals down single cables: DAB, FM, UHF TV (Freeview). Do you do this or do you just use it to distribute TV?
This page might be of interest:
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
Did the device fail before switchover?
At 4 miles you could perhaps have excessive signal levels and thus "may" (perhaps) be able to split the signal quite a few ways without the need for a power booster.
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John Slater: You can view HD at each location using a Freeview HD box at each location.
You can't view HD in a bedroom, for example, that is coming from a box situated in the lounge.
So if you wanted to watch HD in the bedroom, you could do so with either a Freeview HD box and HD TV or a TV with in-built Freeview HD tuner.
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John Slater: There is a diagram on this page which says that all aerial/dish inputs are only fed to the "Living Room" output and that they are not connected to the "Room" outputs.
I gather that you have two coax cables between your loft and living room.
If you are using a Sky box, then there is no need for a splitter as they have two RF outputs.
If you are not using a Sky box, then, where your aerial comes directly into your living room, you can use a splitter to feed the living room TV and the LoftBox. At the LoftBox, the other end of that cable should be connected to the "TV Ant" input.
Then link the "Living Room" output to the "UHF2" input. This is so as to provide DAB and FM (as well as TV) from all "Room" outputs.
If you fed the cable from the living room into "UHF2", then you would only have TV signals at your "Room" outputs (which is what the first paragraph of my response says).
If you require FM and DAB in your living room, then you will have to utilise the other cable between your loft and living room, connecting it to a "Room" output.
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John Slater: Sorry, didn't provide the links.
There is a diagram part way down this page:
http://www.letsautomate.c….cfm
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ian thomas: No, there isn't likely to be more channels available from "Lite" transmitters. This is because those that don't broadcast from Mynydd Machen (the Commercial or "COM" broadcasters) operate on a commercial/profit making basis only and have no Public Service obligation.
The COMs achieve 90% coverage of the population by transmitting from 81 of the largest transmitters (largest by viewer population). The cost to broadcast from the other 1,000 or so small relay sites is roughly equal to that which they already pay. As their objective is to show advertising to as many viewers as possible which they aquire at lowest possible cost, it is easy to see why they don't bother with the small transmitters.
However, it would appear that your area may be served by Mendip which does broadcast the full complement of channels. Streetview shows a number of aerials in your road on Mendip.
This will obviously give you BBC One West and ITV1 West regional programming. It will also give you Channel 4 HD, instead of S4C Clirlun.
If regional programming is important to you, then you could retain your current aerial, either keeping it separate or combining it (with a diplexer) to the Mendip one so as to give you channels from both transmitters on the one downlead.
I understand that the BT Vision box does not have manual tuning, so it could be a bit tricky getting it tuned in to the desired transmitter.
I'm not a professional, but I have read that some recording devices don't fair well when working with more than one transmitter. They have issues with automatic recording.
If you decide to go down the two-aerials diplexed route, then the worst scenario is that you use them separately. That is, your BT Vision (or other recording box) is tuned exclusively to Mendip and you have a set-top box receiver solely for local programming.
See this page for the six Freeview multiplexes, each of which is carried on a single signal:
DMOL Post-DSO Multiplex Channel Allocations
Those with a bullet in the columns "W"/Wales and "E"/England apply for the respective transmitter.
Mynydd Machen carries PSBs only, whereas Mendip carries PSBs and COMs.
The Sky Sports services that are available as part of the BT Vision package are carried on COM6.
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ian thomas: A variation on this is to have another aerial (on Mendip) installed, complete with another downlead to your living room. This will obviously give you two aerial points by your TV.
WIth that, you could either use each aerial separately (e.g. one feeding into one box and another feeding another), or combine them using a diplexer situated in your living room.
If the diplexer is on the roof, then it's not as easy to change.
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John Snowden: Perhaps the problem is a Group B aerial which needs replacing. See this posting I made on this point in relation to the Sudbury transmitter:
Freeview reception - all about aerials | ukfree.tv - 10 years of independent, free digital TV advice
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John Snowden: Also see above postings. It "may" be that Sudbury is not in its final state and therefore it might be worth waiting a little longer before replacing the aerial.
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malcolm: Your biggest issue will be finding some summer to enjoy your summer house.
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Brian Norris: See:
Belmont TV Transmitter
A look on Streetview at your post code (photo taken April 2009) shows quite a few aerials on Emley Moor. I'd estimate maybe a 40/60 split in favour of Emley.
Number 73 appears to have a log. These are native widebands and have a flatter gain curve than yagis. See:
Aerials, TV Aerial and Digital Aerial
I suppose that this particular aerial was fitted to pick up analogue Channel 5 and/or pre-switchover digital which were lower power than the digital signals now. With that in mind, it would seem logical conclude that such an aerial will be sufficient now.
It might be a Log 40. Maybe a DM Log will work. I am 40 miles away from Belmont, to the north east of Doncaster. I have a DM Log in the loft pointing at Emley Moor. Before I installed it I tuned to C22 and C25 and got a healthy mid-80% signal strength on my Sony RDR-HXD870 when pointing the aerial out the first floor window in the direction of Belmont.
Before you do this, it might be worth checking that there isn't water in the cable or joins. Check that the cable hasn't chafed on tiles, for example.
If you do replace the cable, then it is probably best to use copper foil double-screened cable (e.g. WF100):
Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads
Obviously get someone to do it who has the proper tools, ladders and knowledge to work safely at heights.
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Brian Norris: It might be worth discounting the LoftBox as being the cause, possibly through over-amplification. If there is a variable control, then try turning it down.
See Freeview signals: too much of a good thing is bad for you | ukfree.tv - 10 years of independent, free digital TV advice
The PSBs are at higher power than the COMs from Belmont.
The "DM Log" and "Log 40" are different aerials.
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Peter berry: Which transmitter is your aerial directed to?
If it is the Saltdean relay then you will not receive ITV3 or any other Commercial channels from it because it doesn't broadcast them.
If it is Whitehawk Hill, then perhaps you are marginal. Do you get the other Commercial channels?
See this page and identify which of the COM multiplexes (if any) you get:
http://www.dmol.co.uk/mux….php
ITV3 is carried on COM4. So do you get COM5 (Pick TV) and COM6 (Yesterday)?
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Alex: Alex: It is unfortunate that, come switchover at Bilsdale, its COM multiplexes are interleaved with the PSBs of Emley Moor, else you may have been able to combine two aerials. I assume that you prefer to watch Yorkshire regional programming over that of North East/Tyne Tees if possible.
Emley's PSBs being 47, 44, 41 and Bilsdale's post-DSO will be 43, 46 and 40.
See this plot of the terrain between you and Emley Moor:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Looking at that plot, the reason that your area is marginal for Emley's signals is due to the high ground around Beckwithshaw and Rigton High Moor.
The problem you've got is that you don't have direct line of sight. Therefore, you are trying to "collect" what signal comes over the brow.
I'm not an aerial installer myself, but I have read that in situations such as yours that it might be better to use a lower gain aerial with amplifier. This makes sense.
The higher the gain of the aerial, the narrower the acceptance angle. This is because "gain" of an aerial (in one direction) comes about as a result of "loss" in other directions.
Digital reception requires a good quality signal. If you have a poor quality small signal and you amplify it, then you get a large poor quality signal. Whilst you can make a signal bigger with an amplifier, you can't make a poor quality signal a good quality one.
Where you have line of sight, clearly you can focus on the "beam". If you think of the signal as being a light, then where there is no direct line of sight, then you may get a "ball" of light shining over the brow. Any objects on the brow will therefore impact what you see. For example, if there are trees, then they will cause a shadow and probably moving shadow at that.
By using a high gain aerial, you are relying on a narrower portion of the "ball" of signal coming over the hill. A wider angle "may" give you a better quality signal.
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Alex: It is worth checking with Virgin Media which regional output is carried on the cable in your area.
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Nick A: The signal strength jumping up and down as you describe sounds like it could be signal overload, particularly bearing in mind your close proximity to the transmitter.
See this page for an explanation and remedy:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - 10 years of independent, free digital TV advice
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Nick A: There are two factors with digital signals:
- strength: this is the level of the signal (level of voltage if you like)
- quality: digital pictures are resolved to digits (numberical values)
A poor quality signal means that the digits are not being received correctly and hence the picture breaks up or cannot be resolved at all.
Receivers have upper thresholds of signal strength that they can operate at.
A hifi system has a similar maximum level above which the signal starts to distort and therefore the quality reduces.
I imagine that when the strength of a digital signal gets to a level that is excessive (or bordering on excessive), then the effect is analogous to distortion of a hifi system's sound output.
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Jonathan: See
Satellite, Television, FM, DAB, Aerial, Coaxial Cable, Plugs, Sockets, Connectors & Leads
If you already have a cable from the aerial to the TV, then it is probably worth trying it as it is.
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Nick A: 1. Signal level meters vary between devices. So the levels indicated by different devices connected to the same aerial may show different levels. If they were more accurate then receivers would be more expensive as they would have to have more accurate components in!
An attenuator will reduce the level of the signals and will rectify the issue if it is caused by too high a signal level.
2. The level of the signal coming out of the aerial cable is relative to the strength of the signal in the air where your aerial is as well as the sensitivity of the aerial.
You have said that the problem seems to have arisen since the power increase of the three Commercial multiplexes from Sudbury last month. Each multiplex is a single signal which carries multiple services. For example, one carries all BBC standard definition services (BBC One, BBC Two, BBC Three etc).
It is not necessarily just the signal in question that is tuned to that can overwhelm a receiver. High power signals on nearby frequencies can do so as well. Since June you have more higher power signals on nearby frequencies.
A solution to a technical problem isn't necessarily clear cut. It is a case of making observations of what is happening and making a change which may seem the most likely. In this case, trying reducing the signal level would seem the most likely possible solution based on what we know. It is also the case that its cost is low.
You may be able to crudely attenuate the signal (reduce its level) by removing the aerial plug and holding it close to the socket (either at the wall socket or the back of the receiver).
Or at your location you may be able to use a set-top aerial. These being to test the theory that it may be too high a signal level.
If it is too high a signal level, then the fact that it works without difficulty sometimes could be explained by signal levels varying a little bit at different times. At certain times they become too high.
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Nick A: It may be worth checking that your receiver is tuned to the signals from Sudbury and that you are, unknowingly, watching the output from a neighbouring transmitter.
Signal strength screens usually give the UHF channel (frequency) that it is tuned to. There are six signals (multiplexes) from Sudbury:
PSB1 | BBC One | C44
PSB2 | ITV1 | C41
PSB3 | BBC One HD | C47 (if applicable)
COM4 | ITV3 | C58
COM5 | Pick TV | C60
COM6 | Yesterday | C56
The "C" numbers are UHF channel numbers.
I have listed one service carried on each multiplex. To identify which multiplex a particular service is carried on, see this page:
http://www.dmol.co.uk/mux….php
Looking at the predictor for your location, Sandy Heath and Crystal Palace are perhaps possibilities. If you find any of the PSBs tuned (incorrectly) to channels in the 20s, then a simple way around this is to run the automatic tuning scan with the aerial unplugged for the first 30% of the scan (or until it gets past C30).
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G. Elstob: 4seven is not available on Freeview areas that haven't switched. You will receive it when Pontop Pike switches in September.
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paul marsh: I think that it's not very likely that you will be able to receive from Winter Hill even though it is only 5.5 miles away.
Have a look around and see if anyone has a horizontally polarised aerial on Winter Hill. This (if there are any) might be a clue as to whether it might be possible. If there aren't any, then it might be because no one else has tried or it might be because it isn't possible.
Other than that, Freesat is probably your best option for additional free-to-air channels. There are some differences in the offerings of Freesat and full Freeview (ITV3 IS on Freesat):
Compare TV | ukfree.tv - 10 years of independent, free digital TV advice
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Sarah: No. Unless you can receive from another transmitter that carries all channels, then you won't get any more Freeview channels.
BT Vision offers Sky Sports and these channels are broadcast over the air and only available from transmitters with the full range of Freeview channels.
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A1batman: The COM channels do not have as wide a coverage as the PSBs. They are only carried on the largest transmitters and in some cases are at lower power, as is the case with The Wrekin.
Have you had your Group A aerial replaced with a wideband (or Group K) one?
How does the strength of PSB1 and PSB2 compare to COM4?
The sensitivity of a Group A aerial will drop off outside of the Group.
For aerial groups, see:
Aerials, TV Aerial and Digital Aerial
Some example gain (sensitivity) curves:
Gain (curves), Again
If you do have a Group A aerial (red tip) and am looking for information, either to be briefed when you get a professional in, or to do it yourself or get a friend who likes heights to do it, then see:
The Wrekin
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Adrian Durrant: Yes they are ERPs.
According to Digital UK predictor and Ofcom's "Digital Switchover Transmitter Details", all of Hastings' six multiplexes are at 1kW:
Ofcom | Digital Switchover Transmitter Details
However, the multiplex licences published by Ofcom, version 7 (27 January 2012) says that the PSBs are 1kW and the COMs are 0.5kW:
Ofcom | Supplementary licence documents in relation to DSO
I understand that the information at the top of this page is sourced from the licences document.
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A1batman: You've posted this question on another page which I've answered:
The Wrekin B transmitter | ukfree.tv - 10 years of independent, free digital TV advice
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Judy Evans: There is an issue with Goodmans GDB3 models whereby they will not receive post-switchover signals that have a negative offset on their UHF channel number. This is the subject of a Digital UK briefing:
http://www.digitaluk.co.u….pdf
There are a number of transmitters that you could be using in Brighton, depending on where you are.
Taking Whitehawk Hill, BBCA multiplex (which carries BBC standard definition services) is on UHF channel 60-, thus it has a negative offset. UHF channel 60 is at a frequency of 786.0MHz whereas 60- is a little bit lower, it being 785.8MHz. This is above C59.
This receiver cannot pick up post-switchover signals that have negative offsets on their channel numbers.
No other multiplexes have a negative offset from Whitehawk, so these would be expected to be receivable with this device.
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Judy Evans: There are some unofficial firmware upgrades for some Vestel boxes and I'm not sure if one may be suitable for the GDB3.
The process requires connection of the box to a computer via a RS232 (serial) connection.
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Fred Selley: You won't receive 4seven on Freeview as it is only available from transmitters that carry all Freeview channels.
I received the same message myself when I switched from BBC to Channel 4, so I can only assume that the message to retune is being broadcast over the air on Channel 4, hence everyone will see it, even if they cannot ever tune to it.
I think that the likely answer at your location is that you won't be able to receive full Freeview. Freesat provides additional channels, including 4seven.
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molly: 4seven is available after switchover in areas that receive all Freeview channels.
If you are receiving from a transmitter that only carries the Public Service multiplexes, then you won't be able to receive 4seven on Freeview.
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David Brown: Weardale transmitter will be only carry the Public Service Broadcaster (PSB) multiplexes after switchover.
This means that it will carry BBC, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services.
For a full list of post-switchover Freeview services, see:
http://www.dmol.co.uk/mux….php
The COMs are not broadcast from Weardale.
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Martin: It does not cost the Licence anything because the Licence goes to the BBC.
If you are in an area where you can receive from one of the English transmitters, such as across the Severn Estuary, then you may be able to pick up Channel 4 HD.
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Teresa: The channels you identify are carried on the Commercial (COM) multiplexes. The ones you have are those carried by the Public Service Broadcaster (PSB) multiplexes. The COMs don't have as wide a coverage as the PSBs and this is mainly because they don't broadcast from the small "filler-in" relay transmitters (which the PSBs do).
The likely cause depends on which transmitter your aerial is facing (and therefore which one you are tuned to):
- If your aerial is directed to the Newton Abbot transmitter then you won't receive the COMs because they don't broadcast from it. This transmitter is at 12 degrees from your location and your aerial will be vertical (elements up/down).
- If your aerial is directed to the Beacon Hill transmitter, then this does carry PSBs and COMs, but a replacement aerial may be needed for the COMs.
The only way you are ever going to receive the COMs is probably going to be from Beacon Hill, "if" you are in a suitable location. As you are on a slope, then what can and can't be picked up might vary house by house.
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Adam Whitehouse: The Commercial multiplexes do not have as wide a coverage as the Public Service ones. They decide where to site their transmitters and have done so at 81 of the largest (by viewer population). This gives them a coverage of 90% of the population. For them to broadcast from the 1,000 or so small relays including Deiniolen, would double their cost of transmission whilst only adding 8.5% of the population to their potential viewer base.
They make money by showing advertising to as many viewers as possible which they aquire at lowest possible cost. They have no "Public Service" obligation". It is not surprising that they don't consider the relays worthwhile.
The Licence fee goes to the BBC which is a Public Service Broadcaster. I do not agree with any suggestion that it should receive less from viewers which the Commercial broadcasters don't wish to serve. In such cases, with less to choose from, there may be more reliance on the BBC.
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Stuart: See
Freeview signals: too much of a good thing is bad for you | ukfree.tv - 10 years of independent, free digital TV advice
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S Brown: No, Assendon isn't likely to carry the Commercial multiplexes, which carry ITV4 and Film 4 among others.
The reason is because the Commercial broadcasters do not have a "Public Service" obligation. They operate purely on a profit-driven basis and cover 90% of the population from 81 of the largest (by viewer population) sites. To include the 1,000 or so small relays including Assendon would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer bases.
Unless you can receive the Commercial multiplexes from another transmitter such as Crystal Palace or Hannington then you won't ever get them.
Freesat may be worth a look for you.
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carl: This is a sure annoyance of the design of some receivers that retune as they see fit. See if there is an option to disable this "function". If not, then maybe you can attenuate all signals (which will bring down all their levels) in the hope that Storeton Granada will continue to be the highest and therefore chosen.
If you are receiving Yorkshire, then you must surely be getting it from Emley Moor which is horizontally polarised. Storeton Granada is vertically polarised, so it must be a strong signal if it keeps defaulting to it when it has opposite polarisation.
If the above doesn't resolve the issue, then Storeton Granada uses only Group A channels, so you could fit a Group A band pass filter which will only allow Group A channels.
Emley Moor is all Group B.
See Aerials, TV Aerial and Digital Aerial
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Nick: In response to your question of 5th July, I referred to the COMs only with respect to Dover because I assumed that you may have wished to pick up the PSBs from one of the Anglia transmitters. If not, then perhaps you may find that Dover's PSBs are also intermittent, probably caused by the mist.
Some devices can't receive channels with negative offsets that are in 8k mode (which is the mode used after switchover). C60 is the only one with a negative offset that Sudbury uses.
Do you have reception on C60 now? Referring to your posting of 11th July @ 7:47PM, could it be that your home-made aerial needs turning a little?
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Mark: A more accurate location would be useful, or at least knowledge of which transmitter you are receiving from.
If you are receiving from any of the small relay transmitters such as World's End, then it doesn't broadcast the Commercial multiplexes which carry ITV4 and others.
There are three Commercial multiplexes; each being a single signal that carries multiple services.
Do you get ITV3 and Pick TV? These are each carried on the other two Commercial multiplexes.
If you have your aerial directed to Crystal Palace, then what is the make and model of your receiver? There is a known issue with some that means that the multiplex that carries ITV4 will not be able to be received from Crystal Palace.
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Jason: The answer probably has more to do with the way in which things work these days. Channels 21 to 37 were ringfenced at switchover to be "sold" to three licencees for them to create their own network.
If there were plans for them to use particular channels at particular transmitters than this would be in effect telling them what transmitters they had to use.
The ringfencing of 31 to 37 is complete nonsense that has resulted in some areas have clashing channels as well as others with out of group channels when they otherwise wouldn't have been.
I agree that from a practical engineering point of view that channels within group should have been allocated where possible, but that isn't the way things are done these days.
A "free market" approach must be taken which means sacrifices. In a free market, providers have choices as to where they serve and consumers have the choice whether to consume. If it means that the latter have to fork out for a new aerial, then so be it.
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Mark: There is an issue with Goodmans GDB3 models whereby they will not receive post-switchover signals that have a negative offset on their UHF channel number. This is the subject of a Digital UK bulletin:
http://www.digitaluk.co.u….pdf
Post-switchover, one out of six of Crystal Palace's multiplexes have a negative offset and it is the one which carries ITV4, Film 4, Yesterday and others.
It is on UHF channel 28-, thus it has a negative offset. UHF channel 28 is at a frequency of 530.0MHz whereas 28- is a little bit lower, it being at 529.8MHz. The negative offset therefore means that it is a frequency slightly lower than the "centre" of the channel, but above a positive offset of the channel below.
There are some unofficial firmware upgrades for some Vestel boxes (of which this is one) and I'm not sure if one may be suitable for the GDB3. The process requires connection of the box to a computer via a RS232 (serial) connection. This may fix the problem, but if you do it, then you take the chance that it might never work again.
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Mark: Put something like goodmands gdb3 firmware or vestel gdb3 firmware into Google.
I read that the firmware for GDB2 is NOT compatible with GDB3 and vice versa.
As I say, upgrade at your own risk.
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Linda Dale: You asked a similar question the week before last which got two responses:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - 10 years of independent, free digital TV advice
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Bob: I think that it is doubtful. Your best bet is probably to focus on reception from Darvel.
** After writing the text below, I looked at Ofcom's multiplex licences document and each of Darvel's COMs have a note by them saying that they are using the reserve antenna until 24th October 2012, which is when Northern Ireland switches to digital. This will be to protect against interference there and suggests that reception of Darvel COMs may improve on that date. **
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The Digital UK predictor suggests that reception of the PSBs from Rosneath are "good", but it is all "poor" for the COMs. Also, Rosneath uses Group C/D channels whereas Darvel's are all Group A. This is likely to require a different aerial (see below).
The Commercial multiplexes (COM) don't have as good a coverage as the Public Service Broadcaster (PSB) ones. C29 from Darvel is COM6 (or "ArqB") multiplex.
This difference in coverage is due to the small relay transmitters such as Milburn Muir not carrying the COMs, and due to some which do radiating them at lower powers than their PSBs.
The COMs from Darvel and Rosneath are at half the transmission power of respective PSBs. So this probably accounts for the marked difference of Rosneath PSBs vs COMs in the prediction by Digital UK. This doesn't mean that you will definately not pick them up, but as a gauge of "likelihood of success" would tend to suggest that it is unlikely.
The difficulty with reception from Rosneath is due to the high ground somewhere in the area of High Milndovan.
As I say, Darvel uses exclusively channels within Group A and Rosneath uses only Group C/D ones. Wideband yagi aerials are a compromise. There is a sacrifice of gain on individual channels for the benefit of being more sensitive over the whole band. For this reason, it is best to use a Group aerial for the respective transmitter. This is particularly so for Darvel as the gain of yagi aerials is lower at lower channels. So a wideband yagi has less gain on Group A channels. Manufacturers tend to quote gain figures on channels where their products are most sensitive, which is likely to be channels above Group A.
For an explanation of Groups, see:
Aerials, TV Aerial and Digital Aerial
Then refer to this page for some example gain curves:
Gain (curves), Again
If you look at the curves in the bottom-most graph on that page (Wideband curves), you will see that sensitivity of wideband yagis is lower on Group A channels.
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Noel White: The Rowridge transmitter has been broadcasting all six multiplexes horizontally and vertically since 18th April. However, whilst PSBs are at 200kW horizontally and vertically, the COMs are 50kW horizontally and 200kW vertically.
If your aerial is still horizontal, then it might be that the higher power PSB signals are acting to make your receivers less sensitive to the (relatively) lower power COMs.
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Mike: Unfortunately the likely answer is "never".
The Bampton transmitter only carries Public Service Broadcaster (PSB) multiplexes, just like 1,000 or so similar small relay transmitters. The Commercial (COM) multiplex operators achieve a coverage of 90% of the population from 81 of the largest transmitters (largest by viewer population).
For them to transmit from the relays would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer bases. As they operate for profit and have no "Public Service" obligation, they opted not to invest in the relays.
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Mike O'H: I don't believe so. Perhaps there is something that is reflecting (more) signal to your location and which wasn't present before.
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Bob: If you need any parts or information on doing the job yourself, then you might like to take a look at www.aerialsandtv.com
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M Rowland: You do not appear to have line of sight with the top of the Ridge Hill mast. The area in or around Westhope Hill is in the way with the slope being treelined.
The pixelation could be caused by damp in the woods. Does it happen more during dark?
See this page for a trace between your and the transmitter:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
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Shirley: Sudbury would seem the most likely transmitter at your father's location and looking at Streetview, I can't see a house that doesn't have an aerial on this transmitter. Sudbury is 30 degrees which is between north and north east.
The most common issue with Sudbury is that a different aerial "may" be needed to receive Commercial multiplexes/signals. Has your father had a new aerial?
Try and tune ITV3 in manually if the TV has such a facility. From Sudbury it is on UHF channel 58. Depending on the design of the receiver, it may indicate signal strength when you do this. This may give a clue as to whether there is a low signal which isn't great enough to give a picture.
Presumably you attempted a retune on 27th June. Can Pick TV (number 11) be picked up now? And can Yesterday (number 12) be picked up? If not, then the cause may be the same as with ITV3 - an aerial installed in the days of four-channel analogue.
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Nick: Negative offset means that the signal is centred 200kHz lower than the "centre" of the channel. A positive offset is 200kHz above the centre of the channel.
For example, C60 is centred on 786.0MHz, C60- is 785.8MHz and C60+ is 786.2MHz.
In all but a handful of cases, PSBs are on channels within the former four-channel analogue Groups for each transmitter. Where possible, COMs are also in Group, but there are now a number of high power transmitters that have COMs outside of their native Groups.
Sudbury's three PSBs are in Group B and its COMs are in C/D.
Tacolneston's PSBs are Group C/D and its COMs are Group B.
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Joe Griffiths: Which channels are breaking up? Have you confirmed that your receiver is tuned to Wenvoe for all channels?
The Van Terrace transmitter one mile away is co-channel with Wenvoe's COMs, although it is vertically polarised and only 2W.
If your Mynydd Machen aerial is Group A (red tip), then it isn't suitable for Wenvoe, which is exclusively Group B. See:
Aerials, TV Aerial and Digital Aerial
If it is a wideband aerial, then a Group B one of similar size will give better gain.
Wenvoe's COMs are half-power to its PSBs. The COMs also use a less robust transmission mode. These two factors "could" mean that the outcome is that they are unavailable, even if the PSBs are.
At present you only get PSB channels. The COMs are restricted to main stations and high power relays.
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Paul H: Waltham (assuming this is the transmitter you are using) has five channels in Group C/D and one in Group A (C29 which carries ITV3 etc).
If your aerial is a C/D one (green tip) rather than a wideband one, then this could perhaps explain why it might be suggested that it be replaced.
See the bit at the top of the page under the heading "Groups". A more in-depth look is here: Aerials, TV Aerial and Digital Aerial
It is important to appreciate that aerials don't receive nothing outside of group, but that sensitivities drop off. For some example gain curves that illustrate this point, see Gain (curves), Again
You say that the current aerial works OK for all Freeview channels. If it is a C/D aerial, then it would appear that it is sufficiently sensitive on C29 at your location.
I raise this point not to sway you in any way if it is a C/D aerial, but just to make you aware. You may decide that as it is sufficiently sensitive, to have it put back up again. Or you may decide that "good practice" is to replace the C/D aerial with a wideband one.
Another possibility "may" be to install an aerial in the loft. You could perhaps do it yourself, although obviously there is no guarantee that you will get good reception in the loft.
If you are receiving from Waltham and are looking for some advice, see Waltham TV Transmitter
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Norman: The likely answer is "never".
The Commercial multiplexes which carry ITV3 and ITV4, as well as others like Film4 and Dave do not have as wide a reach as the Public Service multiplexes. The Commercial ones operate solely to generate profit and as such broadcast from 81 of the largest transmitters (largest by viewer population) which gives them a coverage of 90% of the population. To transmit from the 1,000 or so small "filler-in" relay sites like Linnet Valley would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer bases.
The Digital UK predictor suggests that you might be able to receive the full service from Tacolneston or Sudbury. I looked down your road on Streetview and can see a few aerials on these main transmitters.
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Jim Charters: Perhaps your aerial is too sensitive for the location and supplying an OTT signal:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - 10 years of independent, free digital TV advice
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lindsey: In your general area the signals from Rowridge come in quite strong. Bring up the signal strength screen whilst on BBC One and see if it is tuned to C24 for Rowridge or C60 for Whitehawk. There is perhaps an outside chance that it could be on C50 which is Newhaven and is a little off-beam from Whitehawk from your location.
If it is tuned to Rowridge, then the solution is simple; all of Rowridge's channels are low frequency and Whitehawk's are high, so have the aerial lead unplugged for the first 30% of the scan (or until it gets past C35 if it gives channel numbers as it scans them). There is a big gap between the two, so there is a big margin.
If it is tuned to Newhaven, then that will be more tricky. If the receiver has manual tuning, then I would keep the aerial out for a bit longer to miss out Newhaven, knowing that some of Whitehawk's will need manually adding. In this case, keep the aerial out to 61%. Then manually tune Whitehawk's C48 which carries Yesterday, 4seven and others. HD services are on C51 and ITV1, C4 etc are on C53.
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piglet: Prior to switchover, the low power Freeview signals, and maybe analogue Channel 5 were too low a power to be useable at your location. Thus, even "if" the four analogue channels could be received from Whitehawk, there would be nothing to gain over the choice offered by Patcham which was probably a much better signal anyway.
Post-switchover, the equivalent transmission power of Whitehawk is twice that of the former four-channel analogue.
The difficulty is the high-ground that is in the way:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
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Saturday 23 June 2012 8:45PM
Tony Ashby: Dave is carried on COM5 (ArqA) multiplex which is on UHF channel 26 from Hastings transmitter. So if your receiver has manual tuning, attempt a tune to C26.