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?
Monday, 17 October 2011
T Gray: The power levels at Crystal Palace are as they have been since 2003, and have not and will not change until switchover on Wednesday 18th April 2012.
I would have a look at the Freeview reception has changed? | ukfree.tv - independent free digital TV advice page.
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Thursday, 27 October 2011
A
Andrew Tegala12:29 PM
Slough
I live in a block of flats in Slough and am unsure of the aerial system in use but there is a roof top aerial. The estate is relevantly new (2000-2001). The aerial is pointing in the direction of Hannington (to the west). Being in Slough I should be able to pick up Freeview from the Crystal Palace and therefore the London region but instead receive Meridian / BBC South programming.
Could you please advise me on what I needs to be done by my management company to rectify this situation?
My post code is SL1 3GE.
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Andrew's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
Andrew Tegala: The region you receive depends on the direction the aerial points. You will have to ask the company to move the aerial, but it could be more complicated as it will probably be the wrong group, other people who use it will not want to watch London programmes and your system may contain amplifiers that have to be tuned to each frequency.
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Mike Dimmick5:15 PM
Andrew Tegala: To be honest I'm surprised they're using Hannington at all. Slough was always considered part of the London TV region, and Hannington has restricted digital coverage to the east at present. Are there any trees or buildings in the direction of the Crystal Palace transmitter that could be blocking reception?
It is possible to combine the signals from two aerials, one pointing in each direction, but obviously that requires extra outlay.
If the system is channelised, it will currently be handling 11 frequencies (5 analogue, six digital) so there will be some spare slots on it after switchover. You only really need the three PSB multiplexes from the other transmitter, the channels on the SDN, ArqA and ArqB multiplexes are all the same throughout England.
Do a survey of your neighbours, see which service they'd prefer and if they'd be interested in receiving both. The management agent will want to recover the cost somehow, of course.
If the aerial was changed, everyone would lose reception until they retuned, so it would have to be co-ordinated carefully.
You should first check that it's not a problem of too much signal on the Crystal Palace services. What do you get on analogue? What does your Freeview box say if you try to manually tune in on C22 and C25? If the signal strength is higher than for Hannington services but quality is lower, it's likely that the signal level is actually too high - this could be considered a fault on the system.
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Wednesday, 2 November 2011
J
john baker6:52 PM
hi i had a small alba tv with built in freeview and i was able to receive all digital channels , i have got a 42inch hitachi tv with built in freeview the problem is i can not get all the channels i used to get im useing the same aerial i hav even put them side by side and swapped the aerial over the picture on teh s,all is brilliant but the same picture is all patchy on the big tv same channel any hgelp would be great thanks
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Thursday, 3 November 2011
john baker: Please can you tell me your full postcode?
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Tuesday, 22 November 2011
N
neha1:59 PM
London
hey .... i am living in an appartment nd the aerial is shared.i a built in freeview in my tv. but i m not able to receive all the channels specially itv2,channel4,5 .... what should i do about it?
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neha's: mapN's Freeview map terrainN's terrain plot wavesN's frequency data N's Freeview Detailed Coverage
neha: Can you try manually tuning to UHF channel 22 (which carries the missing stations)?
If you don't know how to do it, perhaps it will tell you in the user guide as to how to manually tune.
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Saturday, 10 December 2011
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Jon2:12 PM
Hi
I have 2 HDTVs and a Strato set top box. I can get all channels in good quality through the set top box but only those on multiplex 1, B, C and D through the HDTVs.
I have a new aerial, new cable to a booster box and have replaced the cables from the socket to the TVs. The only remaining thing to replace is the coaxial cable in the walls.
I don't understand how I can get all channels on the set top box but not the HDTVs. It also seems to imply the coaxial cables in the wall are fine.
I live in North London and the Aerial points the same way as all the others.
Any help or suggestions much apprecited.
Thanks
Jon
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