All posts by Mike Dimmick
Below are all of Mike Dimmick's postings, with the most recent are at the bottom of the page.
Tony Scull: The 'no problems' message comes from scraping the BBC's reception website, and this is only done periodically. By clicking through the 'BBC Reception Test' link, I can see there actually was a problem reported from 13:08 to 13:13 today.
To report a problem, go to BBC - Reception problems , select 'No' under 'Does this answer your question' and click Continue. If you keep following through the wizard, eventually you get to a form where you can enter a problem report.
If you still have problems that don't match up with the BBC website, it's possible that you have 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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David Cusworth: Transmitter Engineering is an automated poster that scrapes the BBC Reception and Digital UK Planned Engineering Works pages. Because the wording of these pages can change frequently, older information is de-emphasised. This was to ensure posts from actual humans could be picked out - particularly necessary at sites like Emley Moor where the engineering work went on and on seemingly without end.
In this most recent case, the information is actually the same for the last three posts, but the BBC site reports 'today', then 'yesterday', then gives the actual date. Because the text has changed, the automated process posts a new message, even though the *meaning* of the text hasn't changed.
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Anthony R Lea: You're getting confused between ITV1, ITV2, ITV3 and ITV4, which have different content, and the time-shifted version of those channels, with a '+1' after the channel name. These simply broadcast the same as the main channel, but an hour later, in case you have missed it.
It's a very cheap way to sell more advertising space, or charge more for the same ad space.
In the early days, you might get a message saying that the programme cannot be rebroadcast. That meant the channel didn't pay for the rights to broadcast it again, or the rights to time-shift a live football match.
Also, ITV haven't paid for enough equipment to time-shift all regional content, so you may find that ITV1 +1 has a different news service from ITV1. This is the case both on Freeview and on satellite and cable.
Generally ITV1 is the general entertainment channel, ITV2 is more youth-oriented, ITV3 runs archive content from ITV licencees and occasionally from the BBC, and ITV4 is sports-oriented. Freeview only carries the time-shifted +1 versions of ITV1 and ITV2; ITV3 +1 and ITV4 +1 are available on satellite and cable.
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Judith Lee: Two multiplexes at Mendip moved to their final channels on 28 September, and these final locations clash with the transmissions from Usk.
My guess is that your aerial is horizontally-polarized and pointing at Mendip. Digital UK predict that you should get a reliable service from Usk if you have the right aerial set up correctly.
You will not be able to get the commercial multiplexes from Mendip any more, however.
See Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice for the explanation of why Usk will not get any more services.
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Rod Roberts: *Just* Sky News or are other channels from ArqA missing? If other channels are missing, did you have a problem receiving Film4, ITV4 etc before Wednesday's retune?
If so, you have a problem receiving C67. This could be down to a Sky box or other device with an RF output on C66, C67 or C68. You should set the output to somewhere in the C21 to C30 range.
Another reason is just that higher frequencies carry less well along cables than lower frequencies. I see you're splitting your aerial feed - if you're splitting at the back of the TV, you will probably get better results from splitting as close to the aerial as possible. If you're distributing the output of a Sky box, this is obviously not possible.
ArqA will move to its final channel on 28 March 2012. We don't know yet what it will be, but it will be lower than C60.
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Peter Smith: The reason for transposing on analogue is to avoid ghosting - due to the processing delays in the amplifier, the direct path from the transmitter can be shorter than the path via the cables. If field strengths are high enough, the direct path shows up as a ghost image.
Digital TV is designed to cope with delayed paths - indeed multiple paths are used deliberately in some areas, called a Single Frequency Network - and you should be fine without transposing.
Property managers should look at the appropriate section of the Digital UK website, at Property Managers - Home .
The transmissions *do* include descriptions of where to find other multiplexes belonging to the same transmitter or group, but very few boxes actually pay any attention to that information. (We wish they did, it would save all this retuning hassle!)
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kevin standbridge: If your aerial points to Crystal Palace - which it probably does if your switchover date is April 2012 - the problem is probably that Sandy Heath SDN multiplex also uses C31, the same as the pre-switchover HD transmissions from Crystal Palace. It moved to this channel on 31 August. The exact behaviour will depend on how your aerial handles signals from other directions, and the relative propogation of both transmissions (which changes with the weather and with the time of day).
In my opinion, the planners have made a mistake by moving Sandy Heath SDN to C31. It had to move away from the pre-DSO allocation of C43 as that was needed at Sutton Coldfield, but cannot yet take C51 (the final allocation) as that's still needed elsewhere; it had to go somewhere, but I don't think this was a good choice.
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Brian G: At the link that Briantist provided, the BBC's Reception Problems page. If you're having a problem that isn't shown there, say 'No' to 'Does this answer your question?', click Continue, then keep going through the wizard until you get to the problem report form.
The BBC use a mixture of direct off-air monitoring, reports from a small group of viewers, and reports from the general public. The direct off-air monitoring is typically only at major transmitters.
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Briantist: Update on current power levels - according to Ofcom "Table of Digital Terrestrial Broadcasting Stations for Multiplex Licences" v5:
SDN: C48, 100kW
ArqA: C67, 26kW
ArqB: C52, 25.7kW
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Thursday 29 September 2011 5:12PM
Tony: If it's a shared aerial, get in touch with your landlord or agent. See PARAS - Professional Aerial Riggers Against The Sharks for some more ideas of who to talk to.
The system may need recalibrating or retuning, depending on what sort of system it is. D3&4 should have been OK, though, as it uses BBC One's old channel - I would have expected problems on the commercial multiplexes (SDN, ArqA and ArqB) as they use channels that have never previously been used at Sutton Coldfield.
If you have a Sky box, or something else with an RF output, check that the RF output isn't anywhere near any of the multiplexes. You might get this problem if it was on C37, I suppose, because signals at N+1, N+5 and N+9 are typically affected, though I would expect BBC A to have problems as well. I'd look at putting an RF output somewhere in the C21-C30 range or up at C52-C60.