All posts by Steve Donaldson
Below are all of Steve Donaldson's postings, with the most recent are at the bottom of the page.
Jim Gray: Further to the above, I see the section of your road that is your postcode is sloped, as well as the wider area not being flat. With this in mind it is more difficult to say which ground is higher as this varies along the road.
That said, the trees at the front of Prioryhill (the side facing North Deeside Road) and the side facing the medical centre being so tall do look as if they may be in the signal path to some degree for all properties in your postcode.
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Noleen Logue: BBC Reception [bbc.co.uk/reception] says that the Castlederg transmitter is "Off the air due to a fault" since 05:08 this morning. One of the first questions I always ask when a small relay like this goes off air is, is there power outage to the site?
The NIE powercuts map shows a number of power outage symbols to the south of Castlederg town in the area where the transmitter is, so this may explain the reason it is off air.
Powercheck Live power cut and outage information for Northern Ireland | NIE Networks
Don't attempt to retune as all this will do is clear the correct tuning.
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Jeff: The Valley meanders quite a bit which means you are quite a way off having line-of-sight, with several peaks in the way within four miles of your location. The engineering works could necessitate the transmitter using its reserve antenna and/or going on low power. The reserve antenna is a bit down the mast from the main one at the top, and considering the obstructions in your way, it's easy to see that a reduction in height of the antenna in use at the transmitter could result in difficulty with reception.
Here is a terrain plot between your location (on the left) and the transmitter (on the right):
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
The local multiplexes carry only a few programme channels and use a signal mode which is more resilient. There is a trade-off which means the signal mode employed can't carry as many programme channels.
With respect to the predictor computing "good" reception on COM5 (C33) and the PSBs, "poor" on COM6 (C36) and non-existent on COM4 (C48) then I believe the interfering, co-channel transmitter here is Sutton Coldfield with its two Local TV multiplexes. C48 broadcasts southwards and westwards and C36 which is northwestwards.
Whenever the predictor throws up a result such as this where one or more channels are markedly down on the others, despite them all coming from the same transmitter and at the same power, I have a look around to see if I can work out which transmitter (or transmitters) the predictor may be factoring as possible interferer(s). I seem to recall this isn't the first time I've seen a prediction for Mendip to the south of Sutton Coldfield where C48 has been computed by the predictor as quite a bit down on C33 and C36. Whether this is realistic in practice or whether it is rather pessimistic (in that the potential for interference has been over-exaggerated) I'm not sure.
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Ann Roberts : BBC Reception [bbc.co.uk/reception] advises it is currently working.
However, in the event of a power cut to site it may go off air. SP Energy Networks currently has two incidents listed relating to the postcode of the transmitter, one saying it has been restored and the other saying it is ongoing:
https://www.spenergynetwo…07YN
Of course, this isn't to say it will be all in the same postcode, nor that if some in the postcode have been restored that there aren't others. Suffice to say that it appears that it a power outage might have caused it to go of air, in light of what SP Energy Networks is saying.
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Philip Johns: The St Austell relay got a big power boost at digital switchover in 2009. There was also a change of antenna which sends out more signal particularly in the direction of St Austell and much of its suburbs:
mb21 - The Transmission Gallery
At digital switchover most transmitters stayed at what is effectively the same power, meaning the coverage is the same as with analogue. In a few cases, including here, poor reception areas were identified and coverage improved with a power boost, and in a few instances a new transmitter.
All transmitters broadcast the Public Service Broadcaster (PSB) multiplexes (which carry BBC, ITV1, Channel 4, Channel 5 and some sister channels, and all HD channels). The Commercial (COM) multiplexes are broadcast from main transmitters and generally larger relays.
At switchover, the full complement of channels (PSBs and COMs) became available from 80 or so transmitters covering 90% of the population. Of the 1,000 or so PSB-only relays covering around 9% of the population, it was said that the cost of broadcasting the COMs from them would be roughly the same as that for the network of about 80 transmitters, this leaving aside the fact that there weren't enough frequencies.
The COM multiplexes have no obligation to provide a public service, unlike the PSBs. The COM operators serve the greatest number of viewers for the least cost. The biggest transmitters which serve the most viewers cost less-per-viewer to run than the smaller relays, and this is why the 1000+ relays serving 9% of the population cost about the same as the 80-or-so transmitters that have been full-service since switchover (a few have been added since then).
In a situation where a full-service transmitter is available but can be variable, but where there is a good PSB-only relay then one has to consider:
1. Whether to use the full-service transmitter all the time. This may be sacrificing the reliable PSB reception from the relay in return for adding the COM channels.
2. Whether to use the PSB-only relay. This would mean sacrificing the COM channels (which may be poor at times) in return for stable PSB reception.
3. Whether to have an aerial the relay and the full-service transmitter, and feed one into a set-top box and one into the TV. While this is more costly and requires a set-top box, it may provide resilience of the PSBs while offering the COMs when they can be received.
One may wish to consider how often a channel on one of the COM multiplexes is watched, and how much PSB viewing there is. None of the above options are ideal. At the root is the fact that the COM operators are without obligation to provide a public service by installing small in-fill relays.
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Philip Johns: In addition to the above, if the issue of poor reception relates to the COMs only from Caradon Hill, with the PSBs being good, then there would be no advantage and only disadvantage (loss of COMs) receiving from St Austell instead.
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Jeremy Greenaway: With reference to your location, the Caradon Hill transmitter has a notch in its radiation pattern on the three COM channels, 21, 24 and 27 in your direction. This is due to agreement with France because the Saint-Pern transmitter near Rennes uses those three channels at 79kW. The notch means the signal isn't as strong in the direction of the Saint-Pern transmitter coverage area so as to reduce the potential for its viewers to suffer co-channel interference from Caradon Hill.
The Freeview Detailed Coverage Checker is not showing the predictions per channel at the moment for some reason. However, having checked Google Street View I can see there are several aerials pointing to Plympton on your road. Perhaps the solution may be to use it instead.
Caradon Hill and Plympton offer the same range of channels. Previously there were the COM7 and COM8 multiplexes carrying extra HD channels, and these broadcast from Caradon Hill but not Plympton. When these were on the air there may have been an advantage to using the former, but as they now both transmit the same channels there is no benefit going for Caradon Hill.
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Jeremy Greenaway: The source link for the international agreement between the UK and France I referred to is here:
https://www.anfr.fr/fileadmin/mediatheque/documents/coordination/Accords_par_pays/France_UK_700MHz_Clr_DTT_Agreement_07Dec17_Final_signed.compressed.pdf
There is a PDF file embedded on page 4, "UK TVD and PLT Report". Open it and see pages 40 to 43 for Caradon Hill's patterns.
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John Terry: Boom Radio is carried on the Sound Digital national multiplex on 11A. Sound Digital is the second national commercial multiplex which launched in 2016. Its coverage isn't as extensive the other national commercial digital multiplex, Digital One.
It is unlikely that Kent will get any improvement in coverage of Sound Digital. This is because of international constraints where neighbouring countries have multiplexes on the same channel. In the advertisement for the licence published in July 2014 it says that almost all of Kent will be affected. A multiplex covering Flanders is on 11A.
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This is the advertisement for the licence. See paragraph 4.4 where it says that Kent will be affected by the international constraints:
https://web.archive.org/web/20150203172527/http://licensing.ofcom.org.uk/binaries/radio/digital/nationalradio/advert.pdf
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Wednesday 20 November 2024 12:35PM
Jim Gray: With respect to reception along your road, at 100m or so out is the ground on which Prioryhill sits, to the rear of the medical centre. This is a higher than where you are and it is covered in trees. On Google Street View, standing on North Deeside Road, I can see the trees at the front of Prioryhill are very tall and they are right in your signal path.