All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Graham Worboys: You're not alone! See this page:
Sudbury Arqiva multiplex B changes 16 November - retune required | ukfree.tv - independent free digital TV advice
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Hilary: Emley Moor is roughly south from your location and is about the same direction as satellite dishes point.
If you go to one of the HD channels. Then go into the menu > Others > Diagnostics > Signal information. Next to "Channel" (just above "Frequency") it should say 41 if your aerial is pointing to Emley Moor.
If your aerial is pointing to Emley and it doesn't say 41, then it's not tuned to Emley's HD signal which is therefore the cause of the problem.
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Dale: Prior to switchover (before your leaving do), what channel did you get Mux 2 on?
I ask because if you refer to this document which lists all pre-DSO digital services:
http://www.ofcom.org.uk/s….pdf
According to this, there was "Sudbury" which transmitted all muxes at various powers whose antenna was at 178m. "Sudbury B" was slightly higher at 184m and only transmitted Mux 2.
I am given to understand that the reason for this "B" is because of issues with interference with other countries and that other sites such as Dover and The Wrekin do or did have a "B".
Now for the questions:
1. Is the "Sudbury B" listed in that document the same Sudbury B mast shown here?:
mb21 - The Transmission Gallery
2. We assume that "Sudbury" shown in that document was radiated from a different antenna to that of Sudbury B. But is it ("Sudbury") on the taller mast or the shorter one? That is, are they both on the same mast?
ATV suggests that all pre-DSO DTT came from the shorter mast and identifies the separate array for Mux 2 on C68:
Sudbury Transmitter
3. If "Sudbury B" Mux 2 (68) shown in the document was directional, then there was presumably a null in the radiation pattern of Mux 2 from "Sudbury" (56). Thus C68 was there to (to a degree) fill that null.
If this was the case, then surely all of the "Sudbury" muxes were radiated from the same antenna array which would mean that they all had that same null. So did that mean that there were some viewers who could only get Sudbury B's solitary mux?
4. The antenna heights given in that document are puzzling. "Sudbury" was 178m, yet "Sudbury B" was a bit higher at 184m. I can't see how that fits in with the photographs of the masts. Could these figures be the wrong way around?
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Michael: See if you can find out what UHF channel your receiver has tuned to for Pick TV and for Yesterday. This might be on the signal strength screen.
I am wondering if it is tuned to Crystal Palace for these which are on 34+ and 29- respectively. I am wondering if there are issues with the EPG/timer having selected channels from different transmitters or regions.
If it is tuned to Sudbury, then they will be 54 and 63.
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Chris Bartram: There are a couple of possibilities (or it could be both).
1. The TV spectrum are known as UHF channel numbers and these are divided into groups. See here:
Aerials, TV Aerial and Digital Aerial
Back in the day when we only had four terrestrial channels, all transmitters used UHF channels that were all in the same group. Aerials tended to be for a specific group and The Wrekin was Group A.
BBC and ITV which are the Public Sector Broadcaster multiplexes (PSBs) are on Group A channels, but the Commercials (COMs) aren't.
If your aerial is Group A, then it will probably explain why your aerial doesn't pick up the COMs as they're higher up in Group B.
There is now the wide proliferation of wideband aerials which, supposedly, cover the whole TV band. The reason is because of what I've explained. Channel 5 analogue sometimes necessitated such measures as well.
2. The COMs are at half power with respect to the PSBs. So if you're not going to get some, then I'd expect these to be lost first.
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Gem: I wouldn't be suspecting the aerial at this stage.
Can you go to Channel 41 manually? Page 13 of the manual suggests that you can and see the strength/quality for it.
Have you got anything else connected to your aerial (e.g. does it go via a Sky box or booster)? Do you have another (preferably roof-top/fixed) aerial you could try which supplies another room?
What percentage signal strength are you getting on the multiplexes you pick up? Check out BBC1, ITV1, ITV2, Pick TV and Yesterday as these are all on different multiplexes.
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Chris: I'm not in the industry, but based on the information from Ofcom and Digital UK I suspect that, in all seriousness, that this situation will remain until 27th June 2012.
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Roy Brassington: What aerials do you have and where do they point (which transmitters/directions)? Do you have two aerials?
Your post code will be helpful as the Digital UK predictor might help with what transmitters you can get.
Did you get ITV West as well, rather than Central? Or do you get ITV West now, but BBC West Midlands?
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Monday 21 November 2011 9:00PM
Hilary: What is the make and model of your PVR?
Is your aerial on Emley Moor? I am thinking that your receiver could be tuned to another transmitter.