All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Des Collier, Ian Grice: Channel 5 were the only applicants. Unless there was some kind of gentlemen's agreement that ITV (or other Channel 3 licensees) and Channel 4 would not bid this time, you have to assume there isn't that much interest at this time.
ITV plc did announce plans to acquire Channel Television at about the same time, perhaps indicating a problem getting agreement among all ITV licensees. The Order directing Ofcom to run these auctions requires any bid from "Channel 3" to represent at least 13 regional licencees. With the acquisition of Channel TV, which completed on 24 November, ITV plc now own 12 plus the national breakfast licence.
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aron: The commercial broadcasters are only required to provide at least as much coverage as they did before switchover started. They have decided not to extend their services to any further transmitters at this stage.
High Wycombe is joint-31st in terms of household coverage, of transmitters that do not carry the commercial multiplexes. There are five transmitters that do, which are predicted to serve fewer households, but - with the exception of Saddleworth - they are all in the Scottish Islands and were considered 'main' transmitters in the analogue network. The coverage statistics are for 'preferred' transmitters, a service from a main transmitter may still be possible.
Most households in High Wycombe are probably covered by the main transmitter at Crystal Palace. This will be getting a significant power boost to increase the digital coverage area to the same as the analogue one, or even a bit larger. Receivers can be desensitised with loud transmissions on adjacent channels, but High Wycombe's broadcasts are right up at the other end of the spectrum from Crystal Palace's.
There are also 'Freeview Lite' relays at West Wycombe, Chepping Wycombe and Micklefield, indicating that this may be a difficult area for reception from Crystal Palace.
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Chris B: The Hannington transmitter has restricted digital coverage to the east. A whole area from Wokingham down to Basingstoke is effectively not covered, or only covered poorly. This is because Hannington uses the same frequencies for digital services as Guildford does for analogue services, and the analogue services had priority when digital was introduced. Digital UK's postcode checker suggests that you are affected, though less severely than if you were further south.
This restriction will start to be lifted from switchover, matching current analogue coverage: 8 February for the BBC channels, 22 February for ITV1, ITV1+1, ITV2, Channel 4, C4+1, E4, More4 and Channel 5. The remaining channels have to remain restricted until Guildford completes switchover on 18 April 2012.
You must retune on both 8 and 22 February as services move to different frequencies - taking over some of the old analogue frequencies. You may need to retune on 18 April if some services aren't picked up.
Loft aerials are unlikely to become damaged due to weather, unless of course your roof leaks! Also, you still might have trouble if the cable runs outside, particularly if there are any junction boxes. However, signal strength is reduced when passing through the roof or walls, and there's a greater chance of signals from elsewhere being picked up, due to reflections off other surfaces.
A wideband is not necessary for reception from Hannington - all transmissions before and after switchover are in the analogue group, Group E. Future changes might change this, but no changes are expected for at least two years.
There is a deliberate moratorium on works over the Christmas period. Engineering generally is carried out from February to November, the weather isn't suitable for any mast works in winter. No faults have been reported. Signal propogation - how well the signal travels from the transmitter to your aerial - does vary with weather conditions, and these can either increase or reduce signal strength or interference, and can do so differently on different frequencies.
As you have recently retuned, your TV may have decided to tune in another transmitter, such as Crystal Palace, rather than Hannington. If so, see Digital Regional Overlap for thoughts on how to fix this.
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Dave Lindsay: Anything reported via the BBC - with [BBC] at the end - is a fault, not planned engineering works.
The BBC only report faults on their own channels: BBC One and BBC Two analogue, and Mux 1 (BBC One/Two/Three) and B (BBC Four/CBeebies, BBC Parliament). Faults on ITV/C4 etc are not recorded.
The high winds today would mean any planned engineering works would probably have had to be suspended anyway. There weren't any planned for this week (see
Digital UK - Planned Engineering Works for updates).
James: A total absence of anything usually indicates your aerial has fallen down or been damaged, or that a cable has become disconnected. If you're using an amplifier, check that the power supply is plugged in and switched on and that the fuse hasn't blown.
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colin: I suspect you've only just discovered information that has been known all along; that the commercial multiplexes have to run on lower power until 27 June 2012, because of a clash with Dover. Basically, increasing the power at Sudbury any earlier would cut off services for many viewers of the low-power digital services, and even cause problems for some analogue services. Once Dover has switched over - on 27 June - the restrictions at Sudbury can be lifted, and final channels and power levels can be used. You will need to retune on this date.
Compared to pre-switchover reception, the current coverage might be worse as although the power levels were increased somewhat, the transmission mode was changed, trading off increased capacity for reduced coverage, and the increased power level doesn't quite make up for the mode change. The mode was changed again on 22 November, again to increase capacity, which may have reduced coverage a bit, as there was no power increase to compensate this time.
The mode changes were purely commercial decisions by Arqiva, who had pre-sold the additional capacity on ArqB before Sudbury switched over. The extra capacity was sold to BT to carry Sky Sports 1 and 2. The BBC had agreed to match this extra capacity with their own unused space on Mux B before switchover, so if the ArqB mode had not changed, all viewers paying BT or Top-Up TV for Sky Sports would have lost the channel. (This happened at Mendip, for example.)
This information has all been in Digital UK installer documents (except the detailed information about interim power levels). The brochures sent out have perhaps been too simplified, over-emphasising the idea of two stages and everything's done, when at many sites - and particularly the Anglia region - more stages are required. The Anglia booklet does include additional retune dates in 2011; I think the exact date of Dover's switchover wasn't announced when it was published, so 2012 dates weren't included. Some indication should have been made of further retunes being required in 2012.
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Fawley closed on 25 March 2009. It had to give up C34 so that Rowridge could use it, to free up some channels for Stockland Hill PSBs.
The one-channel relays at North Winchester, Hythe (Hants) and Hatch Bottom - which were built to transmit the 'correct' ITV1 subregion to a few areas when Meridian introduced the 'north' service from Hannington - will presumably close when Rowridge closes, although they are already essentially redundant as ITV plc have closed the 'north' service, and will be redundant from 22 February as all other services will be digital, from Hannington. It depends whether there are any frequency clashes with transmitters in the Hannington or Midhurst groups. Midhurst itself will use C59 for ArqA, which is currently used by Hythe (Hants), but it could be restricted to 5 kW until after DSO 1 in the Meridian East region (20 June 2012).
KMJ,Derby: Yes, this information is in Ofcom's 'Table of Digital Stations' at Ofcom | Supplementary licence documents in relation to DSO . Woodbridge Mux B is temporarily on C57 until 27 June 2012. Wivenhoe Park D3&4 is also on C64, not C51 as had previously been advised.
It looks like Ofcom are not going to update the 'DSO Details' information any more. They should really replace it with a pointer to the correct information in the Licensing section.
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NottsUK: Probably for the imminent BBC One HD Scotland, Wales, and Northern Ireland services, then.
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Hannah: If the TV doesn't have a digital tuner built in, you will need a new set-top box before switchover happens in April. If you could previously get ITV2, BBC Three or similar on the TV itself, more than just BBC One, Two, ITV1, C4 and C5, it has a digital tuner.
Only getting Channel 5 is unusual. Have you retuned your TV's analogue tuner since moving? Some apartment blocks with a distribution system - often called a Master Antenna TV system - use transposers to reduce ghosting problems which occur when the direct signal from the transmitter is pretty strong, but not strong enough to use directly. The transposer puts the signal from the wall socket on a different frequency from the one broadcast from the transmitter. That might mean that your TV would need to be tuned to different frequencies than the ones listed at the Crystal Palace web page.
It's also possible that you were using a relay transmitter before; in this case, again you would need to retune the TV's analogue tuner.
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John Andrews: As long as you can connect the box to the TV, you can watch.
The SCART connector is probably the easiest way to connect. While broadcast transmission standards were a little different, the way that pictures are sent on a cable is the same in both countries. You may need to check that both the box and TV are set to RGB or to CVBS mode - this setting controls whether colour is sent on three separate wires, one for each colour, or all combined onto one wire.
If the box and TV support a digital connection like HDMI, that's an even better solution.
You might not be able to use an RF connection, even if the box has an RF modulator that supports it. Portugal used PAL colour with 625-line System B/G for analogue transmissions, while we use PAL with System I. The sub-carrier frequency used for audio is a little different, so you may well get pictures but no sound. Newer TVs usually allow you to select the system used, so you might be able to select PAL I rather than PAL B/G on the TV. But if it's that new, it should have SCART sockets!
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Thursday 15 December 2011 7:53PM
Ian: A red button service takes exactly the same amount of space as a regular channel. Possibly slightly more. The vast majority of the space required is the video stream, running at 1.5 - 2 Mbps, and I'm assuming it has to be running the whole time.
Now, you could perhaps suggest that a Derby service should be carried on the same multiplex as a Nottingham service. No argument with that - except that a service from Waltham is not allowed to point towards Derby because the allocated channel clashes with The Wrekin to the west. The Wrekin's coverage area goes as far north as Tarporley and the west side of the Birkenhead peninsula (though I'd expect viewers there to be using Winter Hill even if it doesn't give the best results), which means the axis on which Derby lies, relative to Waltham, is not possible.
This restriction actually means that the Nottingham service won't serve the west side of that city particularly well.
The alternative is a service from Sutton Coldfield, but the channel allocated there - 51 - is already in use at the Littleover relay and therefore cannot be aimed to the north-east at all (it's also used at Emley Moor for the SDN multiplex).
Again, the government is not going to propose stealing capacity from the COM multiplexes. Ofcom are allowed to allocate capacity for PSB services on up to two multiplexes, which they have used to designate capacity for S4C (in Wales) and Channel 5 on the D3&4 multiplex, and for ITV1 HD and Channel 4 HD on BBC B. But you'd have to require the operator - let's assume D3&4 - to free up a slot for each community you wanted to serve, within the whole BBC/ITV sub-region, kicking off far more services than I think you'd want to.