All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Andrew: Legally, the TV licence is required if you own a TV. The fees collected go to the BBC, whose channels are transmitted from all relay transmitters. The BBC only pay the cost of broadcasting their own services, there is no subsidy for other multiplexes or channels.
The commercial multiplex operators simply decided that it wasn't cost effective - that is, it wouldn't bring in enough revenue - to broadcast from any more transmitters. The regulator, Ofcom, decided that they could not be forced.
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Stephen F: Channel 5 is carried on the D3&4 multiplex on C41 (634 MHz), while the BBC channels are on the BBC A multiplex on C44.
What sort of interference are you seeing? For digital interference you would see picture break-up - blocks or lines tearing, or a frozen picture with moving blocks - and/or breaks in the audio (possibly accompanied by clicks). If you're seeing snow, as you would on analogue, this would probably be cross-talk on the SCART connection - try a different SCART lead. If that doesn't help, it could be cross-talk inside the receiver and you should have the box replaced.
If the BT Vision box itself has an RF modulator, and you're tuning the TV into the box as if it were an analogue TV station, try selecting a different channel for the modulator, or using a SCART cable.
If it was a problem with not supporting 8K mode, I would expect it to not be able to tune in BBC and ITV channels at all, not just have interference.
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Richard: I'm afraid that only the Public Service Broadcasters were required by Ofcom to match analogue coverage.
The commercial multiplex operators were offered the option to broadcast from more sites, but they turned it down on cost grounds. They will continue to use the 81 sites they used before switchover. They will broadcast at much higher power, though, so it may be possible to get Emley Moor once it has switched over. If you provide a full postcode I can check this.
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Richard: Because Skipton is quite high-power and covers a fairly large number of homes, I would expect it to be high up the list of sites that are considered, if the commercial operators do decide to add more sites.
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STEVE: I believe you can select any channel from 21 to 68. Just make sure it doesn't clash with a channel used for terrestrial TV where you live.
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Robert Mansell: It looks like you're probably actually using the Emley Moor transmitter, which is yet to switch over.
Early yesterday morning, the Chesterfield transmitter completed switchover, and started using C40, C43 and C46. These clash with multiplex 2, A and B at Emley Moor for the next two weeks - the clashing transmissions from Chesterfield are deliberately on low power to reduce this, but you're quite a way out from Emley Moor so it's affecting you more than most.
Switchover starts on the 7th of September for you, when BBC Two analogue switches off, ITV1 analogue moves to replace it for the two-week switchover period, and high-power BBC digital replaces that. (Low-power Multiplex 1 shuts down. Multiplex A moves to replace it for the two weeks between stage 1 and 2.)
On the 21st, the remaining analogue services shut down, along with the remaining low-power digital services, and the remaining high-power digital services start up. On both days you should retune after 6am, when all changes should be complete.
74% is still a very healthy signal level, you could actually have too much signal after switchover.
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Chris Low: For now I'd go with an 18-element Group A Yagi. The prediction suggests - because it's below 100% with DUK's assumptions - that a log-periodic probably wouldn't have enough gain.
You do not need a wideband for Crystal Palace either now or after switchover, it is unlikely that any new services would start up after switchover that are outside this group. Widebands have to be larger to provide the same amount of gain as a grouped aerial, particularly in Group A.
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Andy B: Go with Wharfedale, if you have a choice. Digital UK's postcode checker suggests that signals from Addingham are going to get trampled by the commercial multiplexes from Bilsdale once it switches over - they use the same frequencies.
The proximity of Addingham means that you're very unlikely to be able to get those commercial multiplexes from Bilsdale - same reason.
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Nick: The regulator was deliberately set up as a soft touch - excuse me, 'light touch' - regulator by the previous government, along the general principle that governments have followed since 1980, that generally the market should rule and the regulator should rubber-stamp whatever the market decides.
Ofcom is *designed* to be useless.
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Thursday 25 August 2011 10:47PM
Simon: Is the aerial set for vertical polarization - elements going up-and-down - or horizontal? If vertical, you should be tuned into the Sheffield transmitter. It could be a case of too much signal - if you have a booster, remove it or turn it down.
If the aerial is set for horizontal polarization - elements going side-to-side - you're too far away for reliable digital reception from Emley Moor at the moment. Emley Moor switchover starts in two weeks, on the 7th of September, when BBC Two analogue switches off, ITV1 analogue moves to replace it, and high-power BBC digital services take over ITV1's frequency. (Low-power Mux 1 is switched off). It completes on 21 September, when all remaining analogue services shut down, and all low-power digital multiplexes are replaced by their high-power counterparts, on different frequencies. You will need to retune on both dates.
There's a possibility that you could be picking up Sheffield's signals powerfully enough for the TV to detect them even if you have the aerial set horizontally. Newer TVs should handle this overlap better, though.