All posts by Chris Roberts
Below are all of Chris Roberts's postings, with the most recent are at the bottom of the page.
Thank you for your interesting response. As the Transmitted Power for these programmes is, I understand the same as before the changeover, I had wondered whether the atmospheric attenuation was greater for 754MHz (C56) than for 586MHz (C35). Otherwise it does not seem to make sense - why the weak signal? It cannot be due to the aerial as my aerial/tv receives a very strong signal for 722MHz (C52) (it is Guildford BUT Vertically polarized) with a Quality rating of 100 and Strength in the 60s.
Thanks again for your interesting and quick response.
Chris Roberts
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What has happened to Al Jazeera HD & BBC News HD and others that used Channels 32 (Hannington) and 33 (Crystal Palace)? (We can receive from both transmitters)
Since last Wednesday (18th April) we cannot get them on any Channel - not even 55, which I understand is the new Channel. Is Channel 55 transmitting? We can receive Channel 56 OK - Forces TV, Free Sports etc. So it is not aerial dependent. Have scanned every channel from 21 to 68 and there is no evidence of these programmes. What is the Channel for Al Jazeera & BBC News HD etc?
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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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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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Re: Al Jazeera and all Channel 55 programmes. Since Hannington changed Channels on 18 April, Channel 56 improved considerably BUT Channel 55 Signal Strength & Quality have fallen to ZERO. I too miss Al Jazeera!, The problem is NOT to do with the aerial frequency response but is co-channel anti-phase interference in which transmissions from Crystal Palace & Hannington cancel each other out - they are both about the same strength and clearly anti-phase. Channel 56, on the other hand, from these transmitters are "in-phase" AND HAVE STRENGTHED OUR SIGNAL POST THE HANNINGTON CHANGE.
This is clearly a POLICY problem and needs to be addressed urgently.
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Great, Fantastic -1645hrs 30 April - Channel 55 restored and quite strong - managed to retune all Channel 55 programmes and all OK. Also all the new channels now working OK. Hope it stays like this!!!
Whoever arranged it - THANKS.
Chris.
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"That's Surrey" - We can get That's Surrey but it is very weak - it is Programme 7 using Channel 33. Which transmitter is transmitting Channel 33? We are in Guildford.
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StevensOnln1's. Thank you for your response. The reason I asked is that I could not believe why the signal strength of "That's Surrey" was so very very weak being transmitted from Guildford. We are only about 5 miles from the transmitter. Our main HD TV (although tuned to Crystal Palace) receives Guildford transmissions well - we can only get "That's Surrey" by going through our recorder as that seems to act as a form of amplification. Our other non HD TV is tuned to Guildford via a loft aerial with amplifier - receiving good Guildford signals BUT NONE from "That's Surrey". WHY ARE THEY TRANSMITTING SUCH A LOWPOWER SIGNAL?
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Hi StevensOnlin1's
Thanks for your interesting and technical reply. Our full post code is: GU1 2XH. Since I emailed you the recorder has retuned itself and deleted "That's Surrey" from its programme list - so I cannot get it on either TV. The HD one still shows it on its programme list but it only gets occasional pictures. The lower tech non HD TV does not even recognise the programme - can a non HD TV receive the programme? Both TVs get "London Live" (Programme 8) - we can get LONDON BUT NOT SURREY!!. Not too worried but interested to know why.
Thanks - Chris.
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Saturday 7 April 2018 9:03AM
Excellent Website and also the comments re C55 & C56. We have a wideband aerial - at times we can get these programmes (just) at other times it is a "No signal". In Guildford we are in a "strong" signal area, receiving Crystal Palace, Guildford repeater and Hannington. Indeed to receive the C55 programmes we have to use C32 from Hannington - again sometimes OK others not. Two questions - 1) Why doesn't the Guildford repeater transmit Cs 55 & 56? and 2) Why cannot the power transmitted from Crystal Palace be increased? - it may only need a 10% or so increase to receive the programmes properly.
BEFORE THIS RECENT CHANNEL CHANGE ALL WAS PERFECT.
Had an excellent visit from a FREEVIEW engineer - even with an aerial amplifier or high gain aerial the signal/noise ratio is very poor and an aerial amplifier overloads the signal quality of the strong channels. He confirmed we have a wide band aerial.