Full Freeview on the Crystal Palace (Greater London, England) transmitter
Brian Butterworth first published this on - UK Free TV
Google Streetview | Google map | Bing map | Google Earth | 51.424,-0.076 or 51°25'26"N 0°4'32"W | SE19 1UE |
The symbol shows the location of the Crystal Palace (Greater London, England) transmitter which serves 4,490,000 homes. The bright green areas shown where the signal from this transmitter is strong, dark green areas are poorer signals. Those parts shown in yellow may have interference on the same frequency from other masts.
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Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which Freeview channels does the Crystal Palace transmitter broadcast?
If you have any kind of Freeview fault, follow this Freeview reset procedure first.Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which BBC and ITV regional news can I watch from the Crystal Palace transmitter?
BBC London 4.9m homes 18.4%
from London W1A 1AA, 12km north-northwest (335°)
to BBC London region - 55 masts.
ITV London News 4.9m homes 18.4%
from London WC1X 8XZ, 11km north-northwest (345°)
to ITV London region - 55 masts.
Are there any self-help relays?
Charlton Athletic | Transposer | Redeveloped north stand Charlton Athletic Football Club | 130 homes |
Deptford | Transposer | south-east London | 100 homes |
Greenford | Transposer | 12 km N Heathrow Airport | 203 homes |
Hendon | Transposer | Graham Park estate | 50 homes |
White City | Transposer | 9 km W central London | 80 homes |
How will the Crystal Palace (Greater London, England) transmission frequencies change over time?
1950s-80s | 1984-97 | 1997-98 | 1998-2012 | 2012-13 | 21 Mar 2018 | ||||
VHF | A K T | A K T | A K T | A K T | W T | ||||
C1 | BBCtvwaves | ||||||||
C22 | ArqA | ArqA | |||||||
C23 | ITVwaves | ITVwaves | ITVwaves | BBCA | BBCA | ||||
C25 | SDN | SDN | |||||||
C26 | BBC1waves | BBC1waves | BBC1waves | D3+4 | D3+4 | ||||
C28 | -ArqB | ArqB | |||||||
C29 | LW | ||||||||
C30 | C4waves | C4waves | C4waves | -BBCB | BBCB | ||||
C33 | BBC2waves | BBC2waves | BBC2waves | com7 | |||||
C35 | com8 | ||||||||
C55tv_off | com7tv_off | ||||||||
C56tv_off | COM8tv_off |
tv_off Being removed from Freeview (for 5G use) after November 2020 / June 2022 - more
Table shows multiplexes names see this article;
green background for transmission frequencies
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W T
waves denotes analogue; digital switchover was 4 Apr 12 and 18 Apr 12.
How do the old analogue and currrent digital signal levels compare?
Analogue 1-4 | 1000kW | |
SDN, ARQA, ARQB, BBCA, D3+4, BBCB | (-7dB) 200kW | |
com7 | (-13.7dB) 43.1kW | |
com8 | (-14dB) 39.8kW | |
Mux 1*, Mux 2*, Mux A*, Mux B*, Mux C*, Mux D*, LW | (-17dB) 20kW |
Local transmitter maps
Crystal Palace Freeview Crystal Palace DAB Crystal Palace AM/FM Crystal Palace TV region BBC London LondonWhich companies have run the Channel 3 services in the Crystal Palace transmitter area
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Monday, 23 April 2018
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StevensOnln12:07 PM
Chris Roberts: Those channels are on COM7 which moved to UHF channel 55 last week at Hannington. Have you checked for any loose or damaged cables or connections behind your TV? Please provide a full postcode so that we can see your predicted coverage.
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Steve2:35 PM
Reading
Same here: (RG10 9TS): Since last Wednesday (18th April 2018) we cannot get Channel 55 channels such as BBC News HD again: CH 55: Signal strength 8/10, signal quality 0/10. We can receive Channel 56 OK, still - e.g. BBC 4 HD. (With a new Wideband aerial + Loft amplifier installed on April 9th 2018 both Channel 55 and Channel 56 were fine (after the earlier March 21st re-tune) but only) until April 18th when we lost CH55 (yet kept CH 56)!
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Steve's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
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Colin R8:50 PM
Steve & Chris Roberts: This may be co-channel interference if you can get both Hannington and Crystal Palace. The trouble with the 'subtle and cunning plan' of the transmitting authorities to put Com7 and Com8 on channels 55 and 56 everywhere is that, unless the signals are perfectly sychronised at all transmitters, then out of phase signals start to cancel each other out (completely at 180 degrees out of phase).
So it may be that the two transmissions of the Com7 mux on channel 55 at Crystal Palace and Hannington may be, by coincidence, quite out of phase, and hence the interference is causing signal quality 0, but the two Com8 mux transmissions on channel 56, may be by coincidence, in phase, and hence you can receive it.
I am in Weybridge, and although I am much closer to CP than Hannington, ever since 18 April, I am now getting intermittent pixellation on channel 55 mux channels such as BBC News HD, because of interference from Hannington off the back of my shiny new (since the March CP channel changes put paid to my old group A aerial) wideband aerial.
This is what comes of letting Baldrick design a channel strategy that breaks all of the cardinal principals that have governed UHF transmitter channel grouping and mapping for fifty years!
Or more's to the point, rather than a tongue-in-cheek reference to Blackadder, this is in fact what happens when the government goes for a dash for cash from selling off first the 800Mhz TV band for 4G mobile data, and now hastily preparing for selling off the 700MHz TV band for 5G mobile data! All the old channel and aerial groupings that were designed to prevent just this sort of interference seem to have been thrown out of the window.
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Colin R11:10 PM
Colin R: In my previous post I didn't make suggestions for fixing the problem. Well, short of writing to Ofcom and your MP to complain, you might try:
a) experimenting with different levels of gain on the amplifier, if your amplifier has variable gain, and if not, trying an alternative variable gain amplifier. Turning down the gain may just reduce the unwanted weaker signal to a level that lets your TV or PVR receiver resolve the stronger signal without interference and lock on.
b) experimenting with rotating the aerial by up to about fifteen degrees either way, possibly combined with a higher amplifier gain. This will reduce the main signal, assuming that the aerial is currently perfectly pointing at your preferred transmitter, but hopefull not so much as to make it too weak for the receiver, particularly with a bit more amplification. Crucially though, it may move the other transmitter into a a low gain or null lobe of the aerial's reception polar plot, thus significantly reducing or eliminating that other unwanted signal.
c) experimenting with pointing the aerial at the other transmitter, e.g. if currently pointing at Crystal Palace then point it at Hannington instead, and vice-versa, possibly also combined with a) and b) above.
d) if your aerial is in the loft, try it outside, combined with a), b) or c) above if necessary.
A useful gadget when doing the above if your budget stretches to about 35 quid is a Sathero or equivalent digital terrestial finder. These are more expensive than other so-called signal finders, but the advantage is that it will show the signal strength and quality on each channel separately, whereas the cheaper models just show, or claim to show, overall signal strength across all channels.
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Tuesday, 24 April 2018
NICKADSLUK
12:24 AM
12:24 AM
Colin R: well stated Colin
I'm going to wait for a while as I get 10 across the board for quality in crawley where I live on a group a aerial on CP and I don't fancy getting a wideband to muck up what's already perfect just for a few HD channels missing
I use the sat dish for BBC4 HD etc and that works a treat. however its still a hassle in going from terrestrial to free sat on the latest Samsung TV as you have 2 remotes and only one of them will allow to get to that menu for changing over
whoever come up with this changing of channels hadn't really a clue because if you had to remove some channels no problem but any one with common sense would not have removed the HD channels where they are likely to not to work for the majority without additional expense
Remove them all if you must but to remove just a few and leave a few that makes no sense at all
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Colin R3:05 AM
NICKADSLUK: I agree with you about the hassle of switching between Freeview and Freesat.
Unfortunately those of us with both Freeview and Freesat receivers, e.g. many recent model TVs, and group A aerials for Crystal Palace, suffered a double whammy this year when firstly Channel 4 removed Channel 4 HD from Freesat, and then just a month later, the Com7 and Com8 at CP moved to channels 55 and 56.
This means that either you have to keep switching between Freesat for e.g. BBC News HD, and Freeview for e.g. Channel 4 HD, or you have to shell out hard-earned cash to get a wideband aerial, because Freeview won't give you a free wideband aerial if you have satellite capability - perhaps a triple whammy!
Also, if you want to watch Channel 4 + 1 HD and 4seven HD then then the only option is a wideband aerial because these are not on group A channels any more, and nor are they on Freesat.
So the government might be raking in billions in licences for 5G, but it is 'taxing' some of the four and a half million people that are served by Crystal Palace who now have to shell out money for new wideband aerials, or put up with at least some channels lost, if they have both Freeview and Freesat.
Miffed of Weybridge!
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Colin R3:26 AM
Colin R: .... and then, just when you have forked out for a new wideband aerial and you think it is safe to go back into the kitchen (or wherever else your telly is)....
... you get co-channel interference because all the transmitters are being changed to broadcast Com7 and Com8 on the same channels 55 and 56! Aaarrgghhh!!
It's really is the final straw, isn't it?
Extremely miffed of Weybridge
Dear Philip Hammond MP........
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Colin R4:37 AM
Colin R: .... and sadly, no, it's not even the final straw. It has been said that channels 55 and 56 have been chosen for Com7 and Com8 because they will lie in a narrow gap of the 700Mhz band (743 - 757MHz) that won't be used for 5G, at least initially from 2020.
But that still means that frequencies from 700-740MHz and 760-800MHz will probably be used for 5G. If you happen to have a mobile antenna mast nearby your home, or on the line of sight to your TV transmitter (my nearest mast is 600 metres from my house at about 20 degrees off the line of sight) then your TV receiver is likely to be swamped by the strong adjacent 5G signals, thus losing reception of channels 55 and 56.
This is because TV terrestial receivers are actually designed to receive all of the 700MHz band (and the 800Mhz band as well up to channel 68 at 850MHz), and being consumer electronics, and not professional communications receivers costing thousands that have special band-pass and notch filters to filter out strong local transmissions on adjacent frequencies, the so-called automatic gain control in the receiver will probably desensitise it so much because of the relatively strong local 5G signals that TV channels 55 and 56, ususally broadcast with much lower power than the other multiplexes anyway, will no longer get through other than for people who live quite close to the TV transmitter.
So after all this hassle and wideband aerial cost, come 2020 many of us might find that we can't receive the Com7 and Com8 muxs after all, and our new aerial purchase only lasted to get us these channels for a couple more years!
It is also said, that by 2022 Com7 and Com8 might move again, presumably to lower channels / frequencies that are below the 700Mhz 5G and 800MHz 4G bands. This just leaves Baldrick to explain why they were ever moved to ch55 and 56 in the first place!
Does anyone get the feeling, like I do, that the government would like to sell off the entire UHF TV specturm to mobile data serivces sometime in the next ten or twenty years, and shut down terrestial TV altogether? All these recent less-than-user-friendly changes may be a way of 'encouraging' people to switch to satellite TV, or in due course to most TV being delivered by broadband Internet. It may be no coincidence that Ofcom recently set OpenReach and other broadband infrastructure providers a target of a minimum of 10Mb/s broadband to all homes, i.e. sufficient bandwidth to be able to watch any television channel of your choice. It may be feasible, and it may even be reasonable by then, but it would be nice if there was some open and honest communication of the strategy, if this is indeed the case.
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Chris Roberts10:29 AM
1) Re StevensOnin1 2.07pm comment - Thanks for your prompt reply - there is no loose connection etc. Everything is fine on all other Channels both directly to the TV and via the recorder. I think Colin R may have solved it - see below. Our post Code is a GU1 - hope that helps.
2) Colin R's 8.50pm comment is great. It looks as though we are suffering from co-channel interference - thus nothing I can do about it!! Before 18 April we could get a very weak channel 55 signal - now we have none (Strength and Quality). Our aerial points to Crystal Palace and are tuned to London but because we are in a good signal area it also gets a strong signal from Hannington as well. Since 18 April, Channel 56 has improved in strength and quality and we can now get consistent programmes from this Channel. In respect of Channel 55, at least Baldrick had "a cunning plan" - these planners don't!!
3) There must be a change in policy/implementation or something as we have lost important TV Channels for ever.
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Wednesday, 25 April 2018
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Chris Roberts11:17 AM
Hi - as a Postscript to yesterday's comment. Clearly when Hannington moved to Channels 55 & 56 on the 18th April, it enhanced our reception on Channel 56 by an in-phase addition to the Crystal Palace transmissions for us (GU1 post code) BUT for Channel 55 it was, I believe, an out of phase (ie 180 degrees) alignment - cancelling completely any programmes on Channel 55 (Signal Strength & Quality now register 0 - before 18 April it registered about 5 for both - out of 100).
Could/can Hannington change its phasing for Channel 55 so it is in addition to Crystal Palace rather than negating its signal BUT leaving Channel 56 untouched? It appears others are having the same problems.
Thanks - Chris.
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