All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Robert Ewins: There is a two-tier terrestrial television transmitter network. The Public Service Broadcaster (PSB) channels have the same coverage as the former four-channel analogue and the Commercial (COM) networks fit in where possible (and where they wish to invest in transmission equipment).
Many smaller transmitters only carry PSB channels and in some areas reception of COMs isn't possible even though the transmitter being used broadcasts them, this usually being because of interference from another transmitter.
At your mother's location (assuming it to be the postcode associated with your posting) aerials would appear to be facing Crystal Palace. The COM channels are co-channel (same frequencies) as those of Rowridge, which is the main transmitter situated on the Isle of Wight and serving the south coast. For this reason Crystal Palace's COMs may be unavailable or intermittent.
If your mother's aerial faces the Alton relay transmitter, which is surrounded by trees to her south east then this only carries PSB channels.
The only transmitter she "might" be able to get the full service from is Hannington, but even though it's only 16 miles away there is no line-of-sight due to the high ground (which is also tree covered) to the north west of Alton. See this terrain plot:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
If I've got it right and aerials generally face Crystal Palace then perhaps this is because Hannington isn't possible. In which case, maybe she won't be able to receive COM channels.
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Robert Ewins: That's certainly a possibility.
There are six main Freeview multiplexes (signals), including the COMs. One service from each multiplex is:
PSB1 - BBC One
PSB2 - ITV
PSB3 - BBC One HD
COM4 - ITV3
COM5 - Pick
COM6 - 4Music
It might be worth doing a manual scan on the three Crystal Palace COM channels, these being UHF channels 25, 22 and 28 respectively. Enter/select the channel number but don't press the button to scan/add channels. Instead, wait and see if there is a reading of strength and quality. You might find that there is a signal there (i.e. some strength) but poor quality (perhaps owing to interference from Rowridge).
A signal booster is probably not likely to help. It can make a small good quality signal bigger; if it's poor quality all you will end up with is a bigger poor quality signal.
It might be worth enquiring with neighbours. See if any have, perhaps new-looking, Hannington aerials. See if those people manage to receive the COM channels from Hannington and how reliable it might be. In situations where there is no line-of-sight seasonal changes such as to vegetation between you and the transmitter can have an effect.
Hannington is on a bearing of 313 degrees. Crystal Palace is 62 degrees.
Freesat is the free-to-air satellite platform, so going down the satellite route doesn't have to mean a subscription to Sky.
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Nigel: That does sound odd, but you've got to try something different. Doing the same thing over and over and expecting different results causes insanity.
Try missing out one or more of the Bilsdale COM multiplexes. Tune in PSB2 services from Bilsdale and the two from Oliver's Mount. Then power down and see if Oliver's Mount LCN3 is remembered or forgotten.
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Robert Ewins: I may be wrong - I've been trying to get my bearing on Google Streetview.
I now think that most or all aerials may be pointing to Hannington. In which case the UHF channels for its COMs are 41, 44 and 47 respectively. See what you get when manually tuning.
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Dick Maddock: At switchover. However, it isn't likely to serve you.
Another new transmitter at switchover was Rouncefall which broadcasts PSBs as Single Frequency Networks with Sudbury, meaning that the signals are on the same channels and complement one another (you get the sum of both). As Rouncefall doesn't carry all channels (no COMs) you may find Crystal Palace better for them if Sudbury's COMs aren't good. You could combine the feed from both aerials using a diplexer so as to have all channels and London and Anglia regions available on all TVs (you will need a distribution amplifier).
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Nigel: Perhaps the TV has taken it upon itself to do a full automatic tune which has wiped out what you achieved with much work.
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Michael Gilmartin: See:
Craigkelly Transmitter
Other retailers and models are available. A log periodic is the thing to go for.
The terrain plot shows she is 11.5 miles from the transmitter and that it is probably just obscurred by Corstorphine Hil:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
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Michael Gilmartin: The "DM Log" sold by ATV Sheffield is a Blake DML26WB and it's good because it has flat elements and a bracket that allows the device to be tilted.
The Log 36 is a Vision Products model:
TV & Radio Aerials Catalogue » Vision Products - Powerful Products. Easy Installation. Excellent Value
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S Copeland: Do you get a signal with a different TV or box connected to the same aerial?
Has it been used since switchover? (I can't know when your switchover was because you haven't indicated a location or transmitter.) Some older models won't work after switchover and knowledge of its model number should allow us to check whether this is an affected device.
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Sunday 8 June 2014 12:54PM
RH: Rouncefall was a new transmitter at switchover and improves coverage of BBC East/ITV Anglia in the south of Essex, where reception of Sudbury can be poor.
It doesn't carry all channels so you would have to continue to rely on Crystal Palace for the rest.