All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
David Parker: But Bradford is on the edge of the Pennines and as such the terrain goes up and down. Those who are down in the valleys will therefore be quite a way off having line of sight and therefore will have difficulty, which is why relays such as Idle and Wharfdale exist.
The fact that this is the case does not stop the signal going further for those who do have line of sight. It is not solely the distance from the transmitter but what degree of line-of-sight there is!
I believe that the coverage map at the top of this page assumes an omnidirectional radiation pattern as the powers that be won't release them. The green area reaches County Durham so a signal strong enough to cause interference may go further.
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Edmund Janes: No, the Commercial broadcasters don't wish to pay for the installation and upkeep of transmitter equipment at Portslade and over 1,000 other similar small sites. Unlike the broadcasters that do transmit from Portslade, they have no "Public Service" obligation.
See here for a further explanation:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
A few houses in Graham Close have aerials on Rowridge which will give you the full service. It carries BBC South, unlike Portslade, as a relay of Whitehawk, which now carries BBC South East.
Assuming that you can receive from Rowridge, you could either go for the full service from it or combine with your existing aerial so as to watch BBC South East. Or you may be able to pick up directly from Whitehawk; its post-switchover power is greater than the equivalent former analogue power. The only thing that concerns me about Whitehawk is that the prediction for one of the Commercial channels gets worse in October of this year and I can't see why. I assume that another transmitter somewhere will be changing channel, but can't work out which one.
How feasible these options are will be subject to relevant tests by an installer on-site. You're certainly not in a good area for these transmitters, so you will probably need more of a substantial aerial.
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KMJ,Derby: Thanks. Is it just me or would it not be useful for Digital UK Tradeview to convey this information? Surely the degree to which the co-channel transmitter actually interferes depends on the direction and polarisation of the aerial, as well as its rejection characteristics, particularly in the direction of the interfering transmitter.
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Mary Middleton: You can use a separate set-top box for the Bush TV, connecting it with a scart lead (or HDMI if both have it). Indeed, as your TV can you display HD pictures, you could attach a HD receiver so you can watch the four HD programme channels (you will need to use a HDMI lead to link that receiver and TV).
However, despite the Bush's tuner being so basic, I think that there is a good chance of getting it tuned entirely to Oxford if it gives a percentage or UHF channel number as it scans. This is due to the spacing of the channels which mean that unplugging the aerial trick is a possibility. If it doesn't give a percentage or channel number as it scans, and it is just a bar that goes across the screen, you can have a guess, but it will be more tricky.
When a tuner scans, it looks at channel 21 through to 69.
Oxford's lowest channel is 53 which is BBC One etc.
Hannington's highest is 47 which is Yesterday etc.
So your target is to get it plugged in somewhere between the two. If the signal strength screen gives the channel number, then having completed the scan, you can check each of the following are correct:
BBC One = C53
ITV1 = C60
ITV3 = C62
Pick TV = C59
Yesterday = C55
In October next year C62 is expected to move to C50, so the gap between the two which is your "target" for getting it plugged in, reduces.
You may have to do this a number of times before you get it right. If you get the aerial in too late and it misses BBC on C53, then try again but plug it in sooner. You may find that if you get it in too soon and it scans 47 from Hannington it puts them in the 800s and chooses to go with the Oxford equivalent. The next channel down that Hannington uses and which it may pick up if plugged in too soon is C45 which is its BBC.
Finally, this may be helpful, the programme channels are broadcast in groups of which there are five for standard definition services. See under the heading "After switchover configuration" here:
Freeview multiplexes | ukfree.tv - independent free digital TV advice
So when I gave you the channel numbers above, I referred to the first service in each of these groups. BBC Two and other BBC standard definition TV and radio are on the same channel as BBC One, for example.
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Colin: The three multiplexes that Barskeoch transmits are the Public Service Broadcaster (PSB) ones and there are over 1,000 other Freeview Lite transmitters that each cover a small area.
The other three muxes are operated by the Commercial (COM) broadcasters and they choose where to site their transmitter as they have no "Public Service" obligation. They cover 90% of the population by broadcasting from 81 of the largest sites (largest by population).
The projected cost of them using the rest of the transmitters would roughly double their cost of transmission whilst only adding 8.5% off the population to their potential viewer base. Due to the profit-driven motive of these organisations, they decided not to bother with the smaller transmitters.
For a more in-depth explanation, see Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
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P Thomson: The thing with Belmont is that it used to be Group A only, but is now wideband due to the use of C53 and C60.
Has your daughter's Group A aerial been replaced by a wideband one? Does the signal strength on C60 (Yesterday etc) show as being markedly lower than that of BBC One, ITV1 and ITV3?
If there is manual tuning, tune to C53. See if on the screen it gives you an indication of the level of the signal. Maybe it is just below that needed to work.
The Sheffield transmitter is "semi-"wideband and was wideband for analogue Channel 5, so you may have had your aerial replaced for a similar reason.
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P Thomson: The Blackburn relay uses C53 and C60. It is next to the M1 and beams its signal to its north west. I wonder if this is the problem.
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Saturday 28 April 2012 9:52PM
David Parker: I think that it is possible that Emley Moor's signal could interfere with the Pontop Pike. This would seem to be the only logical explanation for C48 to have this restriction placed on it until the date that Pontop Pike ceases use of that channel.
The "low" power of 87kW is still very high and is higher than quite a few other main stations. So evidently it is anticipated that any potential interference would only be caused above 87kW.