All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Charles Wilson: You live in a bungalow which puts your aerial lower down than with a house and you also appear to be well-hampered by some large oak trees on your road.
My feeling is that this is a signal quality issue rather than a signal strength issue. If so, then it starts at the aerial and, for example no amount of amplification will make the slightest bit of difference.
I see that you made a posting last July complaining of the same issue with the same channel. In July this year C50 is due to move to C40, so if it is a particular frequency that is being hit, as it appears to be, then it might go away when it changes channel.
Granted, you would put up with it until then, but if you do do something to try and solve the issue, be mindful that that work may only be required for the next five months.
I'm not an aerial installer; just a technical bod. Perhaps, if you can do so, turning your aerial a little, preferably so it's pointing nearer to the edge of the tree might help.
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J Smallman: If you can't receive from a main transmitter, that carries all channels, then you won't be able to do anything.
Only the main transmitters, and a few larger relays, carry all channels. Therefore a small proportion of the population only receive the Public Service (PSB) channels. See here for an explanation as to why:
Londonderry (Northern Ireland) digital TV transmitter | ukfree.tv - 10 years of independent, free digital TV advice
What I would say is that it could be a possibility that the Ludlow relay at Whitcliffe was used because it's the easier of the two - if indeed reception from the main transmitter is possible. Obviously before switchover there was nothing to be gain by using the main station as they both provided only the four analogue channels.
Now you need to find out whether it is possible to receive the full service from the main station, Ridge Hill.
If not, then you won't receive any other services via the terrestrial network. I'm not familiar with the TalkTalk box so don't know what else you can get with it via your broadband connection.
The only other alternative is to look to the sky (lower-case "s"); Freesat is a popular free-to-air service, I imagine particularly so for those who are stuck with Freeview Lite.
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Joe: The most common answer to such a question is that the receiver in question does not have a DVB-T2 tuner. Knowledge of the make and model number would allow us to say whether this is the reason or not.
For those that do, when manual tuning it is sometimes necessary to set the mode to DVB-T2 (as against DVB-T for standard definition broadcasts).
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John Fotheringham: It's possible that your TV is tuned to Craigkelly with the aerial pointing at Black Hill.
The signal strength screen usually says which UHF channel (frequency) the set is tuned to.
BBC One | Black Hill=C46 | Craigkelly=C27
STV | Black Hill=C43 | Craigkelly=C24
BBC One HD | Black Hill=C40 | Craigkelly=C21
ITV3, Pick TV and Film4 should be tuned to channels 41, 44 and 47 respectively, although it's less likely that anything else will have been picked up.
Because Craigkelly uses lower channel numbers it will have been found before Black Hill during the automatic tuning scan. If your receiver goes with the first it finds then that might explain why it's done what it's done.
The trick is to unplug the aerial lead for the first 30% (or until it gets past UHF channel 30) so as to miss out Craigkelly (and Darvel come to that).
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Peter Henderson: I wonder whether they would ever do that off their own bat, especially now having accepted the terms of the licences.
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Adrian: The reason is because your TV is picking up and deciding to go with (as a "main" channel) one of the Welsh transmitters, probably Moel y Parc.
Moel y Parc's signals are in the middle of the band and Winter Hill's are further up, so you may be able to have the aerial unplugged for the portion that it scans the unwanted channels.
If the scan gives a percentage as it progresses, then plug in just after 60%. If it gives UHF channel numbers (21 to 69), then Winter Hill's lowest is 54, so make sure you get it in just before it.
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Adrian: I should add that if this turns out to be a regular occurance, then you may have to see what you can do to stop it.
Some receivers that retune themselves have an option within the menu for it; others don't and just do as they please.
On the basis that your aerial faces Winter Hill and doesn't face Moel y Parc it may be likely that the former's signal is stronger. Placing some attenuation in the aerial lead to reduce the level of all signals may well drive down the Moel y Parc levels whilst still leaving Winter Hill's far enough the threshold so as not to affect your viewing. The hope is that it won't ever get to "see" the Moel y Parc signals because they will have been reduced sufficiently.
An example of an attenuator is here (other models and sellers are available):
TV Aerial Attenuator Variable 0-20Db Freeview Digital | eBay
If you have an amplifier, then first off reduce its level of amplification if possible as an attenuator works to reduce the signal whereas an amp acts to increase it.
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d crannage: The COM channels do not have as great a coverage as the PSBs. For a list of Freeview services by multiplex, see:
DTG :: DTT Services by Multiplex
There are three PSB (Public Service) multiplexes, of which PSB3 is the HD one, and three COM (Commercial) multiplexes.
Only the larger transmitters carry the COM channels and of those that do, some are marked down in terms of power with respect to PSBs. In the case of The Wrekin, its COMs are on lower power than its PSBs. So whilst the PSBs may be adequate to reach you, the lower power of the COMs may make them somewhat intermittent.
There is another factor and that is that the COM channels from The Wrekin are outside of the former analogue channel Group and so a replacement aerial may be required.
What I suggest that you do is confirm that you are tuned to The Wrekin (so that you aren't unknowingly thinking that you are when in fact you're watching the output of another transmitter). Bring up the signal strength screen whilst on ITV3, Pick TV and Film4 and observe which UHF/RF channel they are tuned to. For The Wrekin they are 41, 44 and 47 respectively. Sutton Coldfield's are 42, 45 and 39 respectively.
What you can get can only really be determined by an installer whist on site. However, Digital UK suggests Sutton Coldfield might be a better possibility for a full service; much better than The Wrekin.
If you have already had your aerial replaced, then it will be suitable for use on Sutton Coldfield; it will just need turning clockwise 63 degrees. If you haven't had your aerial replaced from the analogue days, then it won't be suitable for Sutton Coldfield and you may find that with a replacement on The Wrekin that it brings in the COMs much better.
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Kenneth Blyth: I think that the most likely possibility is that vegetation is growing in the signal path.
I believe that you are using the Brushford transmitter rather than the Bampton one.
The difficulty is that you don't have line-of-sight to the transmitter, so the signal you are trying to receive is what is coming "over" the brow of Highleigh. With such a low power transmitter, you are probably lucky to get anything at all.
If you picture the signal as being headlights coming towards you but which you cannot see directly because their is a summit in the way, then consider if there were some vegetation on the summit. Clearly it will have the potential to affect the light you see. I imagine that, in principle, vegetation in the path of the signal is not going to be too dissimilar.
To come back to the question of your reception issue, digital signals require both strength and quality:
- The strength of the signal going into the receiver must be above a threshold for it to resolve a picture. Amplification boosts the level of the signal and can be helpful where the signal is too low (but of good quality).
- Quality is the digits not being corrupted. If the vegetation is acting to "mash" the signal, meaning that it is of poor quality, then the only thing to do is try moving your aerial or perhaps a different aerial. No amount of amplification will correct a corrupted signal; quality starts at the aerial.
Observe the strength screen. If it indicates that the signal is there, just it's too low to resolve a picture (below the threshold), then perhaps some amplification might help. If you already have an amplifier, then maybe you can increase its level.
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Tuesday 5 February 2013 12:53PM
JW: Perhaps it's something perculiar to your model of PVR. Maybe you could give the model number.