All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
rod: The most common reason for not receiving HD services is because the TV can show HD pictures but not receive them. Knowledge of make and model number would allow us to ascertain whether this is so for you.
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anne west: Because it is carried on a new quasi-national multiplex (signal) -- known as COM7 -- which also carries BBC Four HD, BBC News HD and other HD services. Even if it was available from Stockland Hill, you would still need a Freeview HD receiver in order to watch it.
COM7 is only available from 30 transmitters, serving about 70% of the population. Its purpose is to encourage uptake of Freeview HD (DVB-T2) receivers, in much the same way as Freeview prior to switchover was to encourage uptake of Freeview (digital) receivers, that also not serving everyone.
The reason it is available from "only" 30 transmitters is to keep costs down as it utilised equipment already in existence, used prior to switchover.
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Darrell Reid: The way in which the signal level repeatedly goes down could be indicative of too high a level, this being akin to having the volume up too high on an audio system -- the outcome being that the sound distorts (loss of quality). If the aerial's own in-built amplifier has a variable control then reduce it. If this stabilises the reception then lower it a little more. Do not be tempted to leave it as high as possible without any breakup to the picture (loss of quality).
The terrain plot suggests that, the terrain at least, is not blocking the line-of-sight to Darvel at 14.5 miles:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
On looking at the map of the area between you and the transmitter, and switching to the satellite photo, I note two things:
1. There are four blocks of flats on Pleasantfield Road and six on Arran Park which could potentially be in the way.
2. There are a couple of houses on Oswald Road which are in line with the signal path rather than facing the transmitter.
In any case, consider which direction the signal is coming from. What could be in the way. Can you move the aerial to somewhere else where there would seem to be fewer obstructions and does this produce better results?
When looking at the level of the signals, concentrate on one service from each multiplex, these being:
PSB1 - BBC One - C22
PSB2 - STV - C25
PSB3 - BBC One HD - C28
COM4 - ITV3 - C23
COM5 - Pick - C26
COM6 - 4Music - C29
COM7 - BBC News HD - C31
I have given UHF channel numbers for Darvel. If you do attempt manual tuning and there is an option for signal mode -- DVB-T or DVB-T2 -- then all are the former except for PSB3 and COM7 which are the latter.
COM7 is on lower power than the others. Therefore, if you can receive it without issue but the others constantly keep dipping then maybe you do have too high a signal level, it being pushed OTT by the amplifier.
Once the box is tuned correctly then do not retune as you will achieve nothing other than wasting time.
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Hilly: Same as everywhere as it was on the Digital One national multiplex and has now been removed so as to provide space for Magic. It will be available on local DAB multiplexes in some areas:
a516digital : The great DAB digital radio station reshuffle: what's changing?
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Mike Cushman: At such close proximity to the transmitter you are hard-pressed not to receive a signal!
Go to the manual tuning part of your TV and enter/select UHF channel 28 but do not press the button to scan/add services. Instead wait and see if it gives an indication as to strength and quality, as in such circumstances the device acts like a poor man's signal meter.
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Mike Cushman: HD services are on UHF channel 30 and UHF channel 33. If there is an option for mode on the manual tuning screen -- DVB-T or DVB-T2 -- then you need to select the latter for these channels (standard definition channels are DVB-T).
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Gordon: It is not on "low" power, it is on its highest power.
COM7 and the future COM8 broadcasts from 30 transmitters only using channels set aside exclusively for them. Thus they must fit in with other transmitters and therefore transmission powers are lower than for the main six multiplexes. They are effectively pre-switchover services, only covering a proportion of the population.
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Paul: There are transmitters in Edinburgh which serve small pockets otherwise not served by the main high-power transmitter which is Craigkelly.
It is visible when standing looking across the Forth. Therefore you should consider where is probably best for your aerial in relation to the transmitter. Clearly, if you are at a window facing away from the transmitter then your chances are lower than facing towards it. The higher up you are the better your chances.
If your TV or box is not tuned to Craigkelly and automatic tuning brings nothing in, even having moved the aerial to somewhere which may appear a better spot then use manual tuning if available.
When manual tuning, enter/select the desired UHF channel number but do not press the button to add services, rather wait and see what strength and quality you have as in such circumstances the device usually acts like a signal meter thus you can move the aerial around to see where might be better -- give it several seconds to catch up though.
Craigkelly's channels are:
PSB1 - BBC One - C27
PSB2 - STV - C24
PSB3 - BBC One HD - C21
COM4 - ITV3 - C42
COM5 - Pick - C45
COM6 - 4Music - C39
COM7 - BBC News HD - C33
Local Edinburgh - ETV - C30
If it is a HD receiver then PSB3 and COM7 are applicable. Should this be the case and the manual tuning screen has an option for signal mode -- DVB-T or DVB-T2 -- then PSB3 and COM7 are the latter and the rest are the former.
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Sunday 4 January 2015 11:22PM
rod: All transmitters carry the HD streams of BBC One, BBC Two, BBC Three, CBBC, ITV and Channel 4.
Lawrence Weston Road is on a slope, so what's possible/likely to be receivable may vary from property to property. However, I have made some general observations:
The transmitter which probably best serves the road is Wenvoe, the main transmitter serving Cardiff and the surrounding area, but obviously this carries Welsh regional programming.
There would appear to be quite a few trees in the way, which may produce erratic reception, this varying depending on when the leaves are on the trees, wind blowing them about, water/ice on them etc.
The Bristol Kings Weston transmitter broadcasts primarily to the south as the radiation pattern shows (go to the transmitter's page and click "Click/touch here to read Is the transmitter output the same in all directions?", which is immediately above the comments).
So these two factors 1. trees obstructing line-of-sight; 2. much lower signal power beamed in your direction may account for why you have difficulty.