Freeview modes
Brian Butterworth published on UK Free TV Two of the Freeview multiplexes (collections of channels) broadcast in one mode known as "64QAM mode, FEC=2/3,", and the other three broadcast in another mode called "64QAM mode, FEC=3/4".
The " FEC=2/3" mode provide a more reliable signal than a "FEC=3/4" mode signal at the same power level, but there is a trade-off that means less digital data can be carried.
This diagram shows the current channels carried on the Freeview system. The wider the box, the more bandwidth is used to carry the pictures. The more bandwidth used for a service, the better the picture quality.
Boxes split horizontally denote channels that occupy the bandwidth at different times of the day.
The third line shows the configuration of the BBC "B" multiplex switchover which is used for HD and is in another mode DVB-T2 256QAM.
64 QAM (3/4) mode
In this mode, the digital TV signal is transmitted in groups of 64 symbols. The "forward error correction" is 2/3, and this results in a bitrate of 24M.1b/s (megabits per second). This can be used to carry up to eight simultaneous television channels.64 QAM (2/3) mode
In this mode, the digital TV signal is transmitted in groups of 16 symbols. The "forward error correction" is 3/4, and this results in a bitrate of 27.1Mb/s. This can be used to carry ten simultaneous television channels.Help with Television sets?
Wednesday, 21 September 2011
Saturday, 1 October 2011
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David Bartlett3:10 PM
Brackley
When switch over happened on the 28th I lost all channels except the BBC channels, I have re-tuned several times including unplugging re-tuning and connecting and re-tuning without any change. I still only have the BBC channels. Is it my areal ?
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David's: mapD's Freeview map terrainD's terrain plot wavesD's frequency data D's Freeview Detailed Coverage
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jb384:31 PM
David Bartlett: If you are using Oxford for reception then try manually tuning Mux Ch60, that being ITV1 etc from Oxford and which transmits on exactly the same power as BBC.
You could maybe also check what signal level (and Mux channel) the BBC is being received at, this to be able to assess your aerial efficiency as well verifying that you aren't using Sandy, as although forecast to cover your area its not as good as from Oxford.
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Tuesday, 11 October 2011
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Mr. E.Ellul7:56 PM
Turriff
Dear Sir`s,
I HAVE JUST INSTALLED FREESAT AND WANT TO CAPTURE THE FREEVIEW CHANNELS TO THE FREESAT.I HAVE FOLLOWED THE MANUFACTURERS INSTRUCTIONS (BUSH SAT. BOX)BUT SEEM TO END UP WITH ONLY ODD CHANNELS.I AM USING YOUR INFORMATION ON BIT RATE(2400)AND 760MHZ FOR FREQUENCY OF 5USA ECT I AM NOT SURE WHAT THE PROBLEM IS.ALL FREEVIEW CHANNELS ARE RECEIVED BY MY TV/AERIAL.ANY ADVICE WOULD BE GREATLY APPRECIATED.
MANY THANKS.
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Mr.'s: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Wednesday, 12 October 2011
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David Lewin5:05 PM
(Only just discovered this wonderful forum - so this dates back to 28 September, when analogue TV signals were finally switched off for Oxford area.)
Can anyone explain why the switch off of analogue TV signals (which we've just endured) should result in dramatically impaired RADIO reception? I know digital TV signals were to be boosted once analogue was killed, but surely UHF TV frequencies are too far from FM radio to interfere? Is this all part of a continuing evil plot by commercial interests to force us onto digital radio, at vast expense? (Unlike TV, where the £10 or so cost of a plug-in tuner is tiny compared to that of a new set, I can't imagine anyone - even in Hong Kong - will be rushing to produce plug-in tuners at a fraction of the cost of my many under-a-fiver radios!).
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Thursday, 13 October 2011
Mr. E.Ellul: I am really confused by that... if your question is about getting 5* and 5USA using Freesat, you can't because the channels are not free-to-air.
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David Lewin: The digital switchover should have no effect whatsoever on FM/AM/DAB radio services.
The only time there are issues is the sites where a new mast has been put up and the radio services have to be moved from one mast to the other.
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Monday, 17 October 2011
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Alex Andrews4:41 PM
We have an issue with reception on the HD channels-we live in CR6 so use the Crystal Palace transmitter.Essentially everything works fine except for HD which for about 3 months now has been intermittent.Sometimes it works fines.Sometimes it has no signal at all.Most often it either starts ok then starts pixellating or starts for a few seconds then shows no signal then starts for a second stops starts until eventually we give up.We've had the aerial okd but can't help thinking as its a low transmission we really need a more powerful aerial rather than lose the tv for a month only to be told its ok.Help please!
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T Gray7:40 PM
London
Hello, 8 days ago various channels on my TV had lines going across them and unable to hear the sound. I've worked out that these channels are on MUX 2 and MUX A. PSB3/BBCB is not working either. I get my reception from the Crystal Palace transmitter. My post code is SE1 in London. I see on the web (https://ukfree.tv/txdetail.php?a=TQ339712) that Crystal Palace has low effective power level for MUX 2 and MUX A. PSB3/BBCB. Will this power level return to normal soon or is this how it will remain and I need to look at getting a new arial? I've done all the suggested reset modes and channel deletions / rescans. I live in an apartment block and so the arial on the roof is shared. My neighbours are having the same issues. Just want to find out before I ask the management to upgrade arial if not already done so. Many thanks for your help in advance. Regards, Tom
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T's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
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