All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Karen: Only the BBC multiplex has launched so far. The D3&4 (ITV, C4, C5) and HD multiplexes will launch on the 15th of June.
To fully check the prediction for you, we need a full postcode.
This page's map is still inaccurate. It doesn't include the radiation pattern, doesn't handle interference from other transmitters, and is based on coarse terrain data, too coarse to be particularly useful.
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Kieran R: I've told you before, the service on multiplexes A, C, and D for you is expected to be poor. That means it will break up from time to time, you're not expected to even get clear reception 50% of the time.
As previously discussed, your best option is Hannington, if you can somehow look over or around the trees blocking line of sight.
After switchover, you are not predicted to get any of the commercial muxes from Crystal Palace. This is because the commercial muxes from Rowridge will use the same frequencies. As far as we know, the broadcasters are not trying to provide a large-area Single Frequency Network, or if they are, you're in the area where it won't work.
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andrew: It's possible that they were looking at your best option, not at the transmitter your aerial actually points at. This is particularly the case if you went to a roadshow rather than them visiting, where the town is mostly covered by a main transmitter and only small areas require the fill-in relay transmitter.
It does look like Ilfracombe requires the relay. You might get a six-multiplex service from Wenvoe, across the Bristol Channel in south Wales, but the prediction is poor due to the same channels being used by the Preseli transmitter.
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May: At 32km distance from a very high-power transmitter, it's quite likely that your problem is due to too much signal. If you have an amplifier, try removing it.
Another possibility is that even though your aerial points to Winter Hill, it picks up enough signal from the Pendle Forest transmitter for the box to detect that, although not enough to be usable. Older boxes use the first signals they find, rather than the strongest version. There should be a status screen somewhere in the menus which tells you which radio channel it's tuned in to. If in the C21 to C28 range, it's picked up Pendle Forest.
Also check whether there's a better version of the channels somewhere else in the programme guide - typically at around 800. If so, again it has probably tuned in Pendle Forest rather than Winter Hill.
To correct this, delete all the channels and manually tune in using the frequencies at the top of the page. If your box or TV has an automatic retuning function, turn it off.
You will need to redo this every time that the box needs retuning - whenever new channels are added, and when the retune to clear C61 and C62 happens (probably some time next year).
See also Digital Region Overlap for some more suggestions.
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Jeff Eastmond: The prediction at your address is for a very high chance of reliable reception from both Mendip and from Wenvoe (south Wales). There are really two possibilities: overload, and region overlap.
There's an upper limit to how much signal any amplifier - and the tuner in your TV or PVR involves an amplifier - can handle without distorting. That distortion results in frequency-shifted copies of the signal. The closer they are to the original, the stronger they are, so adjacent or nearby channels tend to be damaged more than thise that are further apart.
Mux A (C62 from Mendip), which carries Challenge, is currently right next to the BBC A multiplex (C61). It is one-tenth the power at present - it cannot move to its final channel (C48) and power level (same as BBC A, 100kW) because other transmitters are still using that frequency.
If you have any additional amplifiers, try removing them or turning them down. A distribution amplifier should have just enough gain to overcome the losses due to splitting the signal, and no more.
It's also possible that your box is tuning into signals transmitted by Wenvoe, rather than from Mendip. These signals would be weaker than expected because the aerial is pointing the other way, but still strong enough for the box to interpret at least some of the time. Some boxes store the first version they find, rather than the strongest version - Wenvoe's transmissions are on lower frequencies than Mendip's. It could also happen if the box is storing the best quality version, but some damage is occurring to the Mendip versions as described above.
Check which UHF channels are being used for each multiplex. If they don't match the Mendip frequencies, delete the affected channels and manually tune the appropriate frequency from the Mendip list. See Digital Region Overlap for other suggestions.
If it is picking up Wenvoe, note that the frequency and power levels of two of the commercial multiplexes - Mux A/SDN and Mux C/Arqiva A - all changed at the end of April, as they moved to their final positions. This could also explain the loss of Challenge, though you would also have lost a number of other channels.
If you are using Mendip, you will need to retune again on 28 September, when Mux A/SDN moves to its final channel, and Mux C/Arqiva A and Mux D/Arqiva B reach their final channels and power levels. You may need to retune again on 28 March next year when Mux A/SDN changes to its final mode and power level.
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Ronald: I don't think there are any Freesat receivers with UHF modulators. Try rf modulator scart switch connectors phono plug lead adapter for a SCART-to-RF modulator.
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Mr D Wright: There are reports of problems with HD from the Nottingham transmitter over the last couple of days. Check the Nottingham transmitter page for updates, and report the problem to the BBC at BBC - Reception problems (select 'No' for 'Does this answer your question' and click Continue to proceed to the problem report form.)
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Lee: You can find lists of free-to-air channels at Eurobird 1 & Astra 2A/2B/2D at 28.2°E - LyngSat and Satellite directory - KingOfSat .
Dave and Challenge are both encrypted, and require a Sky box and active Sky subscription to watch. Sky's encryption scheme is proprietary and not implemented by any other receivers. Freesat receivers might have a Common Interface slot for a decoder module, but Sky do not provide a decoder that can fit into this slot.
There aren't many channels left that are free-to-air but not in Freesat's EPG. Sky require a lengthy technical change procedure for the channel to add the Freesat EPG data as well as Sky's, so there are a few that haven't applied or it's still pending.
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A.E.Arthur: The Bexhill relay transmitter does not start transmitting until next May, when the parent Heathfield transmitter switches over.
It sounds like the aerial at that address is pointing to some other transmitter that does not yet provide digital services, or possibly a main transmitter that is sufficiently far away, or restricted in some way, so that you can't get digital yet.
If you provide a full postcode, we can see whether Digital UK reckons that Bexhill is the best option, or whether another transmitter would be better.
Note that this will be a 'Freeview Lite' transmitter, providing only the three public service multiplexes. The commercial multiplex operators have refused to transmit from any additional sites.
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Friday 27 May 2011 3:55PM
bob reid: Digital UK's predictor still reckons you will get best results from the Perth relay at present. For a six-multiplex service it reckons your best option will be Black Hill, once that transmitter switches over next month, although most multiplexes are expected to remain poor until late 2012.
Looking at the terrain and distance that does seem pretty unlikely! Still, Black Hill transmits at 10 times the power of Angus, and Angus may not transmit equal power in all directions.