All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Bob: The grey and strike-out are simply meant to indicate the services that close down. It doesn't mean it isn't happening.
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- http://www.rtenl.ie/wp-co….pdf lists the frequencies and powers used by Saorview transmissions at present. It appears (from comments on other boards) that they use 64QAM 2/3 8K 1/32 mode as used by the UK PSBs. The second multiplex is already broadcasting, but only carrying test loops.
Ireland actually received 8 UHF channels per site at the Geneva 2006 Regional Radio Conference, they aren't short of frequencies. Some of the assignments were above C60, which will be cleared in Ireland as it will here.
DTT was going to be mostly-pay in Ireland, as it was originally launched here, but the credit crunch hit them hard. Three different operators were awarded the licences before pulling out. They'd also be entering a market where Sky and cable providers are already hugely dominant; it didn't work here, where Sky's digital service and DTT launched at nearly the same time (although our low-power DTT and poor initial planning meant that getting all services was difficult for many viewers).
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Carl: Different DVB-T and DVB-T2 modes require greater or lesser amounts of signal, relative to the noise and interference on that channel. The ratio required depends on how much line-of-sight is available between the transmitter and the receiving aerial, and the amount of reflected signal that arrives at the receiver as well. The specifications give three scenarios: direct line-of-sight with no reflections and random noise; mostly line-of-sight with some reflection; all reflections and no line-of-sight.
The mode selected for the mini-mux requires 10.7 dB less signal (compared to noise + interference) in the first case, 11.1 dB less in the second, and 12.8 dB in the third, comparing to the mode used for UK PSBs. That makes it approximately equivalent to a PSB transmission with 11.7-19 times the power. It still puts Black Mountain NIMM well down on Divis PSBs (which will be at 100 kW), but in the direction of maximum power, actually not far off COMs, which now require 1.5 - 3 dB more than (1.4 - 2x) the PSBs. Brougher Mountain's coverage will be at least as good as the PSB multiplexes and far better than the COMs, while Carnmoney Hill's will be much greater.
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Briantist, Jeff Williams: BBC One HD will shortly launch national variants for Scotland, Wales and Northern Ireland (no date yet publicised, but it was in the DQF proposals, and in a work plan for 2011/12). However, regional variations are not yet proposed.
The main problem is actually cost of coverage on satellite. A single satellite channel is thought to be cheaper than a nationwide Freeview channel, even without Sky subsidising the costs (and then taking the revenue with the other hand), but each regional variant of BBC One has to be broadcast from the same satellites, so the BBC are effectively paying for 18 channels of space. On Freeview, very few transmitters broadcast more than one regional variant, so the costs don't multiply. (Caldbeck carries North East & Cumbria and Scotland, while Storeton carries North West and Wales, although each have directional antennas for one of the services.).
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Roy Hole: It looks like you're primarily a Crystal Palace viewer. If you retune on the Hannington dates, you should still get Crystal Palace services on the regular channel numbers. Your receiver should also store Hannington services on other channel numbers, but those numbers are not fixed in the specifications. I believe it's recommended that they are stored from 800 onwards, but some boxes just use the next number available after the first copy of all services have been stored (which will be around 312 or so), or fill gaps (there are gaps at 8, 35, 45, 47, 50-59 if you don't have HD, 53 and 55-59 if you do, etc) or use 1000 onwards. Some boxes don't store them at all.
Only the high-power BBC services from Hannington launch tomorrow morning. ITV1, C4 and C5 launch at high power on 22 February. The order you get may depend on whether you retune on both dates, or only after it completes. It's likely that ITV/C4/C5 channels from the South region would be stored before the BBC South set, as they will be on a lower frequency and therefore be found first.
Analogue television only carried a recommended channel number from the late 1990s, and again, there wasn't really a spec for where additional copies of the same channel should be stored, so different TVs may have behaved differently, or behaved differently in different parts of the country.
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Kieran R: As has previously been explained, Hannington has a 'notch' in its low-power digital coverage, with seriously reduced power transmitted to the east. This may be the cause of your current problems, though you have previously mentioned trees between you and the transmitter.
The high-power digital services will eventually transmit from the new main antenna, which does not have this notch. The notch is designed to protect reception of analogue channels from Guildford, so it cannot be fully removed until the London region switchover in April. The power will be increased to the maximum permitted, and the modes will be changed on 22 February, as advertised, however.
BBC A (Mux 1): 8 February (retune tomorrow after 6am)
D3&4, BBC B (Mux 2, B): 22 February
ArqA (Mux C): 4 April
SDN, ArqB (Mux A, D): 18 April
If you don't get all the muxes after retuning on 22 February, you will need to retune on the April dates to get them.
Digital UK's predictor continues to predict a good service for you on all multiplexes; between 22 February and 18 April the commercial muxes are predicted to be worse than now, as the power increase doesn't offset the additional margin needed after the mode changes. After the restriction is removed, 99-100% of locations in your grid square are predicted to get near-error-free reception 99% of the time. That figure *is* calculated on the basis of a good quality, reasonably high-gain, fairly directional roof-top aerial, with reasonably short downlead, without too many obstructions.
You've previously used Crystal Palace. That should be a good option for the PSBs but is expected to be poor for the COMs, as they will use the same frequencies as Rowridge. You're in the zone where Rowridge is too weak to be usable but still too significant a source of interference. The model used in predictions isn't as directional as most aerials actually are, so it may be better than predicted.
Do be aware when retuning that many boxes store the first version of the channels that they find, and any Hannington viewer may find that Crystal Palace is stored first - particularly when retuning after April, when CP will be 10 times its current power level.
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Luna: Check that the aerial is still actually present and pointing in the right direction. It will probably be pointing due east to the Black Hill transmitter, though there are other possible options.
If you're in a block of flats - which it looks like you are - you're probably using a communal aerial system. Check with your landlord, management agent or residents' association. If other people in the building have the same problem, the power to the distribution amplifier has probably failed/tripped out/fuse blown.
Analogue services in Scotland's central belt ended on 22 June 2011, and are being phased out over the rest of the UK this year. The remaining regions are the South-East (February and March, May and June), London (April), North-East England and Northern Ireland (October).
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Dave: You must be watching a different transmitter, the Hannington analogue services went at about 00:06 (BBC One)-00:18 (Channel 4). Unless you mean digital Mux 1 is still running, which I can't actually check - it's too weak, via my Crystal Palace aerial, to tune into. There's a bit more signal on C50 than on C46, and substantially more than on C45, so I assume Mux 1 is still running even though signal quality is shown as 0% for all those channels.
In your area, Hangleton, Brighton Central and Newhaven use the same channels for BBC One and BBC Two analogue as Hannington did up until today.
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Arthur Richards: The services are no longer in a one-to-one relationship with UHF channels. With digital, a single UHF channel can carry many services - at present, between 7 and 11 digital TV services per UHF channel. The combination of channels is called a multiplex.
You can find a list of the UHF channels used for each multiplex, and the services carried within it, at the top of the page. BBC One is carried in the BBC A multiplex on C61.
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Monday 6 February 2012 6:16PM
ukbg: Bulgaria hasn't yet launched digital terrestrial TV - the European Commission objected to the original award of licences because Austria's ORS was excluded, being owned by Austria's state broadcaster ORF. They now plan to launch in 2014.
Bulgaria makes DTT move | Broadband TV News
It's likely that the receiver specification will be the 'E-Book', IEC 62216, rather than the UK's 'D-Book' written by the Digital TV Group. This might cause some incompatible behaviour. It's unlikely that interactive content would work, as the 'UK Profile' of MHEG-5 is unique to the UK and Ireland.
For satellite, the Bulgarian channels appear to be on three different satellite clusters depending on the service operator. The main channels BNT 1 and BNT 2 are encrypted on all three, Satellite BG, Bulsatcomm and Vivacom and using different encryption systems to the UK (well, Vivacom are using VideoGuard, which is Sky's system, but you'd still need to get a card from Vivacom and the EPG may well download from a different place).
To pick up UK PSB channels you'd need a very large dish pointed at 28.2°E - far away from any of the Bulgarian services - as the free-to-air channels use transmitting dishes with a footprint designed to only cover the British Isles, at least at decent power/small dish size.