All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Michael O'Pray: Signal strength usually increases overnight, due to refraction off the atmosphere. This 'tropospheric enhancement' is absolutely normal. The actual effect on your reception depends on whether your local transmitter's propogation is enhanced, or if you start picking up atmospheric signals from a distant transmitter.
Having checked the terrain, I can see that you're in a slightly difficult location. The south face of Borough Hill blocks line-of-sight to Sandy Heath. That means signals are quite a bit lower than they would otherwise be, and higher frequencies are usually worse affected than lower ones. At night, the tropospheric enhancement carries the signal over the terrain and usually that will improve your reception enough to be usable.
Careful re-siting of the antenna might optimize your reception. More height might help a bit, but you'd need a very tall pole to see over the hill. Re-cabling would reduce the amount of signal lost in the cable. Ultimately, though, the only thing that will really help is the power increase in September (and the move to the main antenna that goes with it).
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Steve Maynard: If you had reliable Freeview reception before switchover, you probably now have too much signal. Remove any boosters, and if that doesn't help, try adding an attenuator.
I can check the estimated signal levels if you provide a full postcode.
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Can't speak for Brian's box, but my Humax PVR-9200T has to be put in standby for it to get firmware updates. We've already seen numerous reports of people running very old firmware on this box because it was never put in standby, and experiencing problems that were fixed a long time ago.
The EPG data is transmitted at a pretty slow rate by the broadcasters - it takes a few minutes to trickle in. They broadcast about 8 days' worth at any time - if they happen to be broadcasting day 2 when you switch the box on, it takes a little while for it to get back round to today. It's like reading a long article on Ceefax.
Newer TVs and boxes, particularly PVRs, save the EPG data to persistent memory so that it's instantly available when you switch back on. (After the most recent update to my Humax, it now saves the EPG data to the hard disk when you put it in standby.)
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Lily Carter: Fuzz or snow would indicate that you're trying to use the analogue tuner on the TV. The Wrekin transmitter no longer transmits analogue signals. You will need to select the digital tuner on your TV, if it's integrated, or select the Freeview box if you have one. If you don't have one, you need to buy one.
If you do have a Freeview box, you need to retune it, because the services have all moved or changed.
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Vinny: if signals are marginal at one TV, it usually indicates that there's too much cable between the split point and that set. The longer the cable is, the more signal is dropped.
Ideally, a multi-room system should have a high-gain aerial on the roof, a proper matched splitter as close to the aerial as you can fit it but with approximately equal cable lengths from the splitter to each TV, and just enough amplification to offset the loss in the splitter and the cables.
The worst way is a two-way amplified splitter at the back of each set and the last set going through seven boosters before it gets to the aerial. Each additional amplifier adds additional noise, reducing the margin that the TV has to work with.
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Briantist: It may be opposite to the way Ofcom said a few weeks ago, but it's the way Digital UK are saying now.
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M
Waltham - retune required Wednesday 13 April 2011 | SwitchoversThursday 21 April 2011 3:45PM
Hinckley
Ian: You're really at LE10 0NS? Digital UK's predictor says you haven't a hope in hell of getting successful results from Waltham, at any time, past, present, or in the future.
Your only option is Sutton Coldfield - which should give excellent results.
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Michael O'Pray: When I say 'overnight', that's a simplification. It's due to warm and cool layers in the atmosphere, so it changes as the atmosphere warms and cools. It does take a few hours for the effects of sunlight to alter reception.
The broadcasters have known about the actual radiation pattern of the new aerials since they were put up last year, and the old panels since 1998. ArqB is simply using Mux B's old connection to its old antenna: in fact what they probably did was unplug the Mux B input from that transmitter and plug in the new one for ArqB. They're not allowed to alter anything, and largely they can't alter anything - the whole reason it's up at C67 is because there is no better option, until C48 is freed up by later switchovers. The maximum power is set by the plan and it's the same as the power level used by Mux B so as not to interfere (too much) with other transmitters.
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Jonamat: 'Parking channel' seems to simply mean any change that happens before the official DSO. It's 'parked' out of the way of an impending collision with some other transmission. Their predictions showed that the high-power signals at The Wrekin would seriously affect reception in some parts of Waltham's coverage area.
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Thursday 21 April 2011 2:44PM
Dave: BBC West does not and never has broadcast from Ridge Hill on analogue or digital. There are no plans to add it.
ITV1 West analogue was only added at the end of 2006, as part of ITV plc's reorganization of its news regions. The former Central South news region was split, with Oxford joining Meridian North to produce ITV Thames Valley, and Ridge Hill's main ITV1 frequency transmitting the Central West service from Birmingham, along with the digital service.