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
Sutton Coldfield (Birmingham, England) Full Freeview transmitteThursday 7 April 2011 11:10PM
Reading
Ryan: I really need a full postcode, because the performance can change so much over just a few metres distance.
The prediction for DE55 7HH, the centre of Alfreton, is basically terrible.
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W THAIN: At that postcode you're predicted to have a reasonable chance of getting good results from the Torosay main transmitter, which provides all six multiplexes. This requires a Group A aerial oriented vertically, pointing south-west.
There are no public plans to provide any more channels. The commercial multiplexes turned down the option to broadcast from more sites than they had done before switchover, and they're not required to.
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Tony Davies: The Pace DTR375 is on the list of 2k-only equipment. If you're using a transmitter that's just started switchover and have been prompted to retune this week, I'm afraid the box has become obsolete, it doesn't support the mode that the BBC channels are now transmitted in, and that all other channels will be after the 20th.*
You could try 0000, but it probably wants the code that was entered long, long ago when onDigital was still running and there was a viewing card in it. That's the only reference I can find in the manual:
http://replay.waybackmach….pdf
* Some transmitters have late, post-Step 2, mode changes on some or all of the commercial multiplexes. These channels will continue to work until then. (RG47SH)
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Kelly Ibbotson: Please see Digital Region Overlap for ideas.
One approach is to delete all channels or do a full reset, then cancel the automatic retune. Then manually tune the correct frequencies. For the Winter Hill transmitter, use C62, C59, C58, C61, C55 and C54.
There will be another retune some time in the next year or so to free up C61 and C62. No date is yet set.
If you find it gets reset back again, check your TV's manual to see if it has an automatic background retune feature, and see if you can turn it off.
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Damian: Please see the Single Frequency Interference page. Note that for you, the references to Mux 2 and A being weaker than the others no longer apply - this applied only before switchover.
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iandc: Try it without the booster. You shouldn't need it and it could be harmful.
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301 has moved to Mux 1. This is probably to make space on Mux B for the matched slot on ArqA.
Confirmed by DMOL: DMOL Pre-DSO Multiplex Channel Allocations (RG47SH)
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steve: Last week Mux 1 was at 2 kW, on two different channels depending on whether you were west or east of the transmitter.
Each multiplex has had different levels over the years. The oldest capture archived by WaybackMachine.org is from February 2001, which shows kW on all multiplexes.
The levels were originally set very low because of fears of damage to analogue reception, particularly at the relays. As the damage was not as bad as had been believed, they increased the digital power, changed channels, changed radiation patterns, to improve coverage (some analogue relays were increased in power to compensate, I believe). Some sites like The Wrekin got additional aerials and channels where they couldn't find one set of channels to cover the whole area.
Still, digital has never had the power necessary to match the analogue coverage. The only way to get there is to convert fully - turn off analogue and all the clashes go away, so you can increase digital power up to equal or even greater coverage.
Doing it in two stages is a political choice, so as to give people fair warning that it's about to go and give them some extra time to get sorted out before everything disappears.
The analogue network was planned to provide four networks from the start, so reducing that to three PSB multiplexes is really not a problem. Generally the three PSBs get channels previously used for analogue - BBC A takes BBC One's old channel, D3&4 replaces ITV1. Here, BBC B has a different channel but this is due to releasing channels 31-38.
Fitting in the COM multiplexes is more tricky - six into four doesn't go. They have to go wherever space can be found and often at lower power, costing some coverage. The PSBs are required to meet analogue's 98.5% coverage. The COMs are expected to get 90.5%. They don't really care about that last 8% - they turned down the option to use any additional sites.
As for 16QAM 3/4 vs 64QAM 2/3: the plan was always to use 64QAM and all muxes used that mode from 1998 to 2002. The BBC originally ran a line-up on Mux 1 similar to what is now on BBC A. When ITV Digital went into administration, one of the conditions of the new licences was a mode change to improve coverage. However, the multiplexes granted by law rather than by auction (mux 1, 2 and A) were not compelled to make the change. The BBC did, ITV and S4C didn't, we had a mix of modes for the next six to ten years.
(S4C? Yes. SDN stood for S4C Digital Networks. They flogged it to ITV plc in 2005.)
2001 power levels:
DTT Channel Allocation - The Midlands
'Equalization programme' details from 2001:
DTG :: Page not found plans for increases in 2002 (not all of these happened):
http://www.ofcom.org.uk/s….doc
Post 2002 changes: DTT Transmitting Station alterations (RG47SH)
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David: Can you please see the Channel 4 HD on Freesat page - Channel 4 HD to start on Freesat | ukfree.tv - independent free digital TV advice (RG47SH)
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Thursday 7 April 2011 11:03PM
Chris: Unplug the box, leave it for a few minutes, and plug it back in.
This problem was first reported on Humax boxes. My hypothesis is that the BBC have changed the program ID for the code that pops up the 'Press Red' indicator - reusing a program ID previously used for 'return to last transmission' when you press TEXT to exit the interactive stream. They probably didn't think anyone's box had been on long enough to still have it cached.
Or, they've changed the program and it's not compatible with some MHEG interpreters, but that wouldn't explain why power-cycling the box is working for so many people.
It is recommended that you do a complete retune from scratch at switchover dates, but I can't see how to do this.
I did find this method of doing a software reset:
Digital Spy Forums - View Single Post - Sony VTX-D800U (merged)
That whole thread might be useful. (RG47SH)