All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
jb38: According to Ofcom, some of Sandy Heath's muxes are using the "S1 transitional antenna" until 27th June:
http://licensing.ofcom.or….pdf
These being PSB1, PSB2, PSB3 and COM6 (C48).
The others do not say that they are using that antenna; I'm not sure whether this means that they're not or that they are but it's not been mentioned.
Digital UK Tradeview says "PSB power-up" on 27th June. I wonder if this is related to the change of antenna as, according to DUK, the PSBs are at 180kW now.
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Mike Dimmick: Thanks for the explanation of the transitional antenna. It's very interesting.
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laura: You must be in a location where signals from more than one transmitter overlap one another.
When a receiver performs the automatic tuning scan, it "looks" to see what signals are available. In cases where if finds duplicate channels from different transmitters, it has to decide which to use. In this case it has decided to go with the BBC signal from a different transmitter. Duplicates are usually placed in the 800s.
In cases such as this, poor or erratic reception may ensue because the signal is being received from a direction other than that which the aerial faces.
It is sometimes possible to devise a workaround to this problem where the aerial lead is unplugged for the part of the scan of the frequencies that the offending transmitter uses. To know which part the plug needs removing, we need to know which transmitter is the desired one and which one is being picked up in error.
Knowing your location and direction of your aerial or the transmitter to which your aerial faces will be useful. Also, find out which UHF channels BBC One and ITV1 are tuned to. Do this by bringing up the signal strength screen whilst on each. Most receivers give tuned channel numbers there. This will allow us to work out which transmitters are being received.
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jmp: I should expect that the situation will improve.
The pre-switchover digital signals from Blue Bell Hill use the same frequencies as a number of other transmitters in that general part of the country. So if you happen to be in a spot that picks up a bit of signal from one or more of those transmitters, then they could act to degrade your reception from Blue Bell.
For example, Sandy Heath is co-channel with Blue Bell's current ITV1, C4, C5, ITV3 and others. The Digital UK predictor suggests that you might get a bit of Sandy's signal, and hence it "may" degrade your reception of Blue Bell.
After switchover the situation should improve as the power of Blue Bell will go up and there aren't transmitters in such close proximity that are co-channel (same frequencies).
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K Cooper: Dover is one of a few transmitters that, for its pre-switchover digital, broadcasts some multiplexes on different channels in different directions.
For example, Mux 1, which carries BBC One, BBC Two and some other BBC services, is on C68 and C45. It is not known which faces it radiates each, but I guess that one side will put it out on one channel and the other on the other channel.
There may be overlap, so you may be picking up the one that isn't quite as good for you.
Bluebell Hill uses C45 at the moment, so I would hazard a guess that C68 may be best for you.
What I suggest that you do is go to BBC One and bring up the signal strength screen. See if it tells you whether you are tuned to C68 or C45. Then do a signal check of the other (that you aren't tuned to). How you do this may vary depending on the device. You may have manual tuning or the signal strength screen may allow you to change the UHF channel number so as to "look" a different one. Or you may have to look in the 800s for another BBC One that is coming from Dover. Of course, they may not be one if you are in an area where there is no overlap.
It would also perhaps be useful to know what UHF channels ITV1 and Pick TV are coming in on as they have a similar dual-channel arrangement, them being 61/42 and 62/39 respectively.
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K Cooper: If you find that the other is better, then you will need to get them swapped. If you would like some help, then let us know which is best for BBC, and also which ITV1 and Pick TV seem to be the best as well.
It should be possible to have the aerial unplugged for part of the scan to avoid picking up the one you don't want.
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Ray: Yes, sometimes the automatic tuning procedure can leave the wrong transmitter tuned in.
Hannington and maybe Midhurst look as though they may be possibilities for you. Perhaps swapping to vertical polarisation would also reduce the likelihood of that happening as they are horizontal only.
Looking at the channel allocations for these transmitters, you should be able to unplug the aerial lead at 30% so as to scan Rowridge's channels and avoid those of Hannington and Midhurst.
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Colin Wardley: As previously advised ( Are you really watching free TV in high definition? | ukfree.tv - independent free digital TV advice ) Bluebell Hill does not broadcast HD until 27th June.
Therefore if you received it previously you must have been picking it up from another transmitter. Because this was likely to be off-beam for your aerial, reception was always expected not to be perfect. Therefore it may be hit and miss.
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SJ: Indoor aerials are hit and miss. Any aerial relies on being sited in a spot where it can get a signal and indoors (which is usually below the roof line where there are walls and other obstructions in the direction of the transmitter) is where the signal is less likely to be good.
The aerials in Jay Court point at Waltham, as do those on the main road.
I think that your chances of success with a set-top aerial aren't great because:
- There are three three storey (plus roof) buildings in the direction of Waltham, so they will be reducing the signal.
- The terrace that is parallel to Slack Lane is in the direction of the transmitter. Thus, the closer you live to the end where number 10 is, the more building you have in the way. Even a loft aerial is probably out of the question for the same reason. Conversely, the closer you are to the three storey buildings, the more you are in their shadow.
- If you live in the terrace that is at right-angles to Slack Lane, then you may have a greater chance for rooms that face the direction of the transmitter. Depending on the type of roof (whether it inhibits signal) you may be able to receive using a loft aerial.
All that said, I suggest that you look at extending the fixed aerial that serves your bedroom.
I would get proper stuff and not rely on the DIY kits. See A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial.
An unpowered splitter "may" work. Have a Plan B incase splitting the signal leaves you without sufficient. A solution in such circumstances may be a powered amplifier or perhaps feeding one outlet from another aerial and using the current one for only two outlets.
If you could receive Freeview using the fixed aerial before switchover last August, then you may be able to use a four-way non-powered splitter as the signal levels are now much higher.
With digital reception, signal strength isn't so much an issue; the objective isn't to get the signal strength bar as near 100% as possible. So long as the quality is 100%, then it the picture is as good as it will ever be. Different devices use different scales, so one's 50% strength is different to another's.
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Wednesday 6 June 2012 10:09PM
Rog, jb38: This is interesting and I think you are right Rog, to hold off getting a new aerial.
It may be worth a shot tuning to Sutton Coldfield for these services; you may be able to pick them up off the back of your aerial. They are:
COM4=C42
COM5=C45
COM6=C39
Or Waltham:
COM4=C29
COM5=C56
COM6=C57 (this one is doubtful as Oxford uses C57 as well)
Or Oxford:
COM4=C62
COM5=C59
COM6=C55
This might be worth a shot. Then keep trying 48, 51 and 52 to see if they are available.