All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Rob: They are never likely to broadcast from the Banbridge transmitter. See here for an explanation:
Londonderry transmitter | ukfree.tv - 10 years of independent, free digital TV advice
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Sarah: Assuming that your aerial points to the Crosspool transmitter, as all the aerials on your street appear to be, then you need to manually tune to C39 for COM6 which carries Film4 and Yesterday.
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Sarah: What I am wondering is if there is too much signal. A set-top aerial by its nature picks up less signal due to it being lower to the ground and smaller.
If you have any booster fitted, then remove it (unless it's used to split the signal several ways).
Too high a signal level can appear as too little a signal. That is the higher the signal goes over and above the receiver works reliably at, the more it gets overwhelmed by signal and starts to show poorer quality signal and lower strength. Sometimes this can cause the strength to jump up and down.
I imagine that you might be able to see the transmitter from your roof-top.
See:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - 10 years of independent, free digital TV advice
Variable attenuators are available online from such sources as eBay (other retailers are available), for example:
TV Aerial Attenuator Variable 0-20Db Freeview Digital | eBay
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norm: Carnmoney Hill does not broadcast the Commercial channels and is not likely to ever do so. See here for an explanation:
Londonderry transmitter | ukfree.tv - 10 years of independent, free digital TV advice
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john: As Guisborough sits at the bottom of the moor which carries its name and there are trees on the slopes, it is probably the case that quite a few people in Guisborough will only receive PSBs.
This is because the Guisborough relay transmitter carries only PSB channels and because, for those who receive from Bilsdale directly, its COM channels (those not carried by Guisborough and which you have lost) are on lower transmission power than its PSBs and they use a less robust (less fragile) signal mode.
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john: The "less fragile" should say "more fragile".
Imagine if the signals were a courier service where fragile parcels a received broken but non-fragile ones aren't (i.e. they don't bash them about enough to break the non-fragile ones).
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Don: After switchover, the Freeview network is a two-tier system, as you have found out. Whilst all transmitters carry PSB channels and so serve the same areas as the former analogue, a lot of small transmitters like Lisbellaw don't carry the COM channels. For a list of which are PSB and which are COM, see:
DTG :: DTT Services by Multiplex
The other thing is that of those that do carry the COMs, they are on lower power than the PSBs and hence some on the fringes can only receive PSBs.
From Brougher Mountain there is a very marked difference between power of PSBs (20kW) and power of COMs (2kW). Most that are different have COMs at half power to the PSBs.
If people were receiving the pre-switchover digital from Brougher Mountain with their aerials directed to the Lisbellow relay (which at that time only carried analogue), then from an engineering point of view they were lucky. For reception from Brougher Mountain a Group A aerial is required in areas where the signal is not so good, as I assume it is so in your general area which is why the local relay was installed.
Unless reception of the COMs is possible from Brougher, then there is no advantage to be gained from receiving from it when the signal from the local relay is available.
The marked difference in the strength of PSBs vs COMs could be an issue with tuners desensitising themselves as a result of the high power signals thereby not being sensitive enough to pick up the lower powered ones. Careful adjustment of an amplifier or adjustment of an attenuator may strike a ballance allowing both to be viewed.
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Elizabeth Bellamy: See:
Gold replaces LBC on MXR Yorkshire DAB : Radio Today with RCS
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Thursday 1 November 2012 2:47PM
Martin Engwell: You may end up no better off with Sudbury as with Thetford as the prediction is that you will likely only be able to receive its PSBs.
Of Sudbury's COMs, C56 and C58 are used by Waltham. C60 isn't used by Waltham, although it is used by Oxford and Belmont (which are further away). The prediction for it is "poor".