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, 11 May 2011
Daniel Esmond: Sorry, but your TV is not a Freeview HD - DVB-T2 one. You will need to use a Freeview HD box with the set to watch the channels.
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Colin Hersey: Yes, " After the PSB multiplexes switch at The Wrekin, the Arqiva multiplexes will remain on their pre-switchover frequencies and powers, and SDN will use a temporary frequency, for a short period before all three multiplexes adopt their final frequencies and powers during September 2011. During this transition period the commercial multiplexes will use the following frequencies: SDN ch49 and ch31 (both 2kW), Arqiva A ch57 (not 53) (1kW), Arqiva B ch53 (not 57) (1kW)."
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Friday, 27 May 2011
D
David4:11 PM
Mike Dimmock - thank you for the explaination 64QAM versus 16QAM eh?
Actually, I miss-spoke. Mux A is the only one I cannot receive well at the moment, but it is highly dependant upon the weather and time-of-year.
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Monday, 30 May 2011
M
marilyn5:17 PM
I live in Hanslope mk19 and since the digital switchover have lost itv4 and yesterday any idea why and what can I do to get them back
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marilyn: Bit hard to say without a full postcode, but you are probably using the Sandy Heath transmitter and if so you will have to wait until the ArqB multiplex goes to full power on 14th September 2011.
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Wednesday, 1 June 2011
D
Don Johnstone10:38 PM
BBC 1 and 2 now disappeared since the first part of the Craigkelly switchover.Internal aerials but two different ones that worked fine before this 'improvement'.
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K
KMJ,Derby11:25 PM
Don Johnstone: Did you do a factory reset to remove all memory of the Mux1 versions of BBC1 and BBC2 from the channel list? Check if they are currently in the 800s. If you still don't find Mux BBCA when rescanning after doing a factory reset check that your receiver or STB is not on the list of equipment that does not support the 8k mode. If it is on the list, a new Freeview box is required to continue viewing Freeview after switchover. Note some receivers do not like finding a mix of 2k and 8k mode muxes..Do a manual tune for Mux BBCA on C27 if this is the problem.
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Saturday, 4 June 2011
I
Ian11:40 PM
Kilmarnock
I have 2 sony DVD recorders with HDD and freeview built in, which are in different rooms and both have signal strengths of about 96% and quality is 100%. When I scan for all channels they all appear and are in the EPG, however when I switch the machines off, or they switch off automatically at the end of recordings, once switched back on, about 95% of the EPG is blank ?? I have had these both for over a year, with no problems to date and am serviced from the Darvel transmitter ? As the strengths and qualities are both high I am baffled as to the problem ??
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Ian's: mapI's Freeview map terrainI's terrain plot wavesI's frequency data I's Freeview Detailed Coverage
Sunday, 5 June 2011
Ian: It is quite likely your signal are too strong now. If you have any boosters or amplifiers, remove them from your system.
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Sunday, 26 June 2011
R
Rick12:51 PM
Hitchin
Postcode SG4 7HP. Up until a few weeks ago I could receive all Freeview channels with no problems. Now all the BBCA channels vary from strong to no signal making them unwatchable. Every other MUX works fine. Luckily I can get all BBC channels on Freesat so question is largely academic (though there are times when this is not so good). I have a SONY with built in Freesat and Freeview and a high gain wide band loft mounted aerial pointed at Sandy Heath. All other houses round here have their aerials on long poles but I cannot do this as I live in a listed building. Any solution or do I live with it? Also would an aerial booster help?
Thanks
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Rick's: mapR's Freeview map terrainR's terrain plot wavesR's frequency data R's Freeview Detailed Coverage
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