All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Pat B: Because your TV tuned to the Belmont transmitter which is in Lincolnshire or Emley Moor in Yorkshire. These signals came available to you so far away due to the inversion effect.
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Jackie Kirby: I would take the Dion box to another aerial outlet and tune it in. Having got all the channels tuned in, don't retune (until switchover on 4th and and 18th April).
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Tracy Gill: Following on from Mike Dimmick's suggestion that it could be that your receiver has tuned to Stockland Hill and put Mendip in the 800s, I looked at the channel (frequency) allocations for these transmitters.
If this is your problem, then you should be able to correct it by running the automatic tuning scan with the aerial unplugged up until about 45%.
Stockland Hill uses channels between 22 and 29 and Mendip uses 48 to 61.
You will need to retune on 28th March due to a channel change for Arqiva A which carries Pick TV and others. This will not affect the procedure I outlined above as it is still within that range of channels.
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J Metcalfe: Perhaps it is the inversion effect (follow the link for explanation). The predictor suggests that them multiplex that carries ITV1, C4, C5 and others is marginal.
You will probably have to live with it until switchover when the transmission power is boosted by 10 times.
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Dave: I don't believe that that is the case.
The Ofcom document listing transmitters in the Meridian area shows Patcham to be horizontal:
http://stakeholders.ofcom….pdf
Rowridge is having a vertical component added (so it will still be horizontal and will therefore mean horizontal aerials will still work). Whitehawk has always been vertical and remains so after switchover.
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Alda: Either the display setting is wrong on the TV or it is wrong on the Humax.
I found the user manual on the internet:
http://www.humaxdigital.c….pdf
Referring to page 55 explains how to change it on the Humax.
I am assuming that you have a widescreen TV and therefore the Humax needs to be setup so that this is the case.
Go to the menu > Preferences > Display Format. Change Screen Ratio to 16:9 (which is widescreen).
If this doesn't solve the problem, then post the make and model of your TV and I will suggest something that you might try to rectify the situation.
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James Willmott: The PSBs from Belmont are at 150kW, so on the face of it, if they are OK, then you would have thought that the 100kW COMs should be OK and not too much signal.
However, the gain of wideband yagis is not as good at lower frequencies. See these gain curves on Aerials and TV's website:
Gain (curves), Again
High gain widebands in particular aren't as good on lower channels than on higher ones.
I'm not an aerial installer, so don't know to what degree this might have affect in your situation, but I can only wonder if this is the reason.
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Tim McEwan: Some possibilities:
1. There is another device that is putting out an analogue signal on C21.
2. The TV is "HD Ready" which means that it can show HD pictures, but does not have the means to receive them off air.
What is the make and model of the TV?
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Mark H: The thing is that St Thomas only relays the Public Service Broadcaster (PSB) channels which are BBC, ITV1, ITV2, C4, E4, More4, C5, HD services and some others.
So if you have these perfectly then your receiver is tuned correctly (i.e. to the signals coming from the transmitter to which your aerial faces).
The best commercial (COM) channels it will find are probably Stockland Hill, and hence why reception is poor.
For an explanation of why St Thomas doesn't relay the COMs, see here:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
Whether you can receive a stable signal from Stockland Hill with a suitable aerial is another question. Obviously from a signal strength point of view, St Thomas is probably the one to go for.
You might be high enough to get a signal from Stockland Hill. See here for a plot of the terrain. You have or aren't far off line of sight with it:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
Be aware the COMs from Stockland Hill are at lower power than the PSBs so if you can't get the (weaker) COMs from it, then there's no benefit in moving away from St Thomas.
Until 18th April they are at 10kW when they will be increase to their final power of 25kW. The PSBs are at their final power now which is 50kW.
It might be best to wait until the power increase in April to get another aerial.
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Tuesday 17 January 2012 5:48PM
nicola: It is a possibility that the reason your receiver isn't picking up two of the (weaker) COMs is because the strong PSBs is desensitising your receiver.
That is, it is less sensitive to the weaker COMs because it is reacting to the strong PSBs.
Change to ITV3 and bring up the signal strength meter. Now connect the attenuator into the aerial lead and turn it and see what happens. Get an idea of where the strength is at its highest. See if adding attenuation actually increases it.