All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
M
Nottingham (Nottinghamshire, England) Full Freeview transmitterThursday 6 October 2011 2:54PM
Nottingham
Pixelated: If you had reliable results before switchover, you could have too much signal. I can't advise any more on that or on the possibility of using Waltham without a full postcode.
At NG12 3JL - roughly the centre of Cotgrave - Waltham gives a better chance of reliable reception than Nottingham, or at least will do after the SDN multiplex reaches full power next Wednesday. You would need a wideband aerial for all multiplexes. It looks as though that postcode is shielded slightly by the terrain, so a higher-gain aerial is probably necessary, and I would recommend an outdoor aerial.
ian from notts: Yes, Emley Moor and Nottingham now use the same frequencies for the SDN, ArqA and ArqB multiplexes, since the retune on the 27th. I don't think these are actually co-ordinated so will interfere with each other in some areas.
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John Morris: The cable insulation is plastic and like all plastics, it deteriorates with exposure to sunlight, and can then let damp in. White insulation tends to be affected worse than black or brown.
Cables should be anchored at frequent intervals, including clips over tiles, so that they cannot move in the wind and rub over the brickwork or tiles, which wears through the insulation.
I'd say you should plan to replace cables about every ten years.
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Willie Donaghy: The number of transmitters and power levels for Freeview, before switchover, was necessarily limited to avoid interactions with the Republic. That's why take-up of digital in Northern Ireland has been relatively poor.
It means digital coverage from Limavady isn't anywhere near the analogue coverage area. Four of the digital multiplexes also clash with the Claudy relay. I'm not surprised that it's unreliable out where you are, although Digital UK's postcode checker isn't currently accepting your postcode so I can't see the actual prediction.
Aerials and cables do deteriorate over time with weather exposure, and if water gets into cables, it seriously degrades the cable's performance - and higher frequencies are affected worse than lower ones.
At switchover, the PSB digital transmissions should have parity with the current analogue transmissions, or slightly better. The commercial multiplexes will still only transmit from Divis, Limavady and Brougher Mountain and will be half the power - but that still means they should be nearly the same coverage as analogue, except for a few areas where channels clash with the PSB channels from a relay (Plumbridge and Castlederg).
It looks like switchover is about a year away, stage one on 10 October 2012 and stage two on 24 October. This is based on a leaflet that briefly appeared on Digital UK's website on Friday - my guess is that the announcement is supposed to be on Monday or Tuesday and someone pushed the leaflet out too early.
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K W: I assume you mean Freesat-from-Sky as Freesat does not require a viewing card.
You can set up parental controls on all Sky boxes. See Sky TV | Set up for the manuals for each different type of box, which will show you how to do this.
They do say that the default PIN is the last four digits of the viewing card's serial number - if you don't have the card, and you haven't set the PIN to something else, you will need to contact Sky to find out what it was or to get it changed.
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Phill: Saorview launched at the end of last year.
A Freeview HD receiver should implement MPEG-4 AVC on DVB-T, which is required to receive RT 2 when it's broadcasting in HD, even though at present the UK only uses MPEG-4 AVC on a DVB-T2 multiplex.
For interactive text, the Irish standard permits either MHEG-5 as used in the UK, or the legacy teletext system. Freeview HD equipment is not required to implement legacy teletext.
You can check to see whether the address you'll be using the equipment at is covered by going to Coverage Map | SAORVIEW
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Graeme Young: Yes, BBC A on C61 will have to move, as C61 and C62 are now to be released for 4G mobile in addition to C63-C68 in the original plan. All stations with greater than 1kW ERP output are subject to international co-ordination - although the plan from 2006 shows that Waltham did not need to be co-ordinated with anyone else. Still, the co-ordination required for other sites like Tacolneston, Mendip, Wenvoe (not itself affected directly but it might have to move out of the way of Mendip) means that Waltham is unlikely to make an earlier move than other sites.
C21-C30 are retained for TV broadcasting - they are not going to force the 4.4 million Londoners using Crystal Palace to all buy new aerials (well, unless they're completely mad). The SDN multiplex on C29 is very unlikely to have to move.
You may need to retune the SDN multiplex early tomorrow, as it reaches full power and changes to 8K mode. Changes are supposed to be complete by 6am.
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Craig: Boosters are typically no use whatsoever. They are only of any use if the receiver is particularly noisy, and most Freeview boxes will actually be less noisy than an added booster.
The prediction at your address is 100% across the board, suggesting that the problem is actually too *much* signal. See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice .
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Nicholas: The standard Freeview EPG is transmitted on all multiplexes. Each multiplex transmits its own information more frequently than others, and information about programmes coming up sooner more frequently than later events, but it does all get sent and repeat after a few minutes. Some boxes can get very confused with a mix of different services from different transmitters.
I'd start off by doing a full reset or first-time installation with the aerial unplugged, then doing a manual search for the transmissions from your most preferred transmitters. If that is then reliable, do a manual search for just the regional services (BBC A and D3&4) on your second preferred transmitter, which will put those services in the 800s. If it stops being reliable after that, you'll know where the problem lies.
Some equipment does still use a proprietary EPG. Top-Up TV's EPG is attached to TOPUP Anytime 1, Guide+ to bid.tv, and RadioTimes Extra to Television X. All three are on Mux A/SDN.
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Paul: Ofcom's official documentation of Sutton Coldfield's frequencies was re-issued in January this year, to move BBC B's allocated channel from C50 to C40, and ArqB from C49 to C39. This is part of the plan to free C61 and C62 for 4G mobiles - basically C39 and C40 were going to be freed but are now kept. However, a direct move from C62 to C40 or C61 to C39 would affect a lot of people, as they aren't in the same group, so the compromise is *generally* to move allocations of C62 to C50 and C61 to C49, and move C50 to C40 and C49 to C39, where there is a clash.
Yes, this means there will be another retune at Oxford some time in the next two years, to move SDN from C62 to somewhere else, although it *should* remain in Group C/D.
Hannington C50 isn't particularly low at 20kW, that actually made it joint equal most powerful pre-switchover transmitter, with Crystal Palace, Rowridge and Sandy Heath! Post-switchover PSB power levels are only 4 dB higher at 50 kW (COM power levels are 1 dB higher than at present, 25 kW).
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Thursday 6 October 2011 2:43PM
BobH: Existing recordings are preserved when you use the 'Default Setting' option, which is recommended with major retunes. In the latest firmware 1.00.23, 'Automatic Search' is supposed to be equivalent for retuning, but I still found scheduled recordings could be unreliable unless you delete the schedule and re-create it.
Default Setting resets all other preferences, so you will have to reset the output format option (reverts to 4:3 with letterboxing), the UHF output channel, and the recording schedule (that being the minimum that I do).