All posts by Steve
Below are all of Steve's postings, with the most recent are at the bottom of the page.
Hi. I live in Sevenoaks, Kent and have always received good Freeview from Crystal Palace transmitter - both before and after switchover. My main TV is connected to a rooftop digital aerial which is boosted and pointing at CP and I have another TV connected to an indoor aerial which is also boosted and pointing at CP. I'm currently getting excellent reception from both TV's. However, yesterday I received a message on my main TV telling me that I would have to retune on 9th May? - else I'd lose some channels. I only received this message on the TV connected to the rooftop aerial - not on the other TV connected to the indoor aerial. Interestingly, while retuning on the 18th April, my main TV showed some channels were apparently coming from Cambridge? Is there a transmitter in the Cambridge area which is about to be switched over during May? - and could I be receiving channels through my rooftop aerial to my main TV from two transmitters?
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Thanks Tim. Question is - If I retune as message suggests will I then get Sandy Heath local news etc? I would much rather stick with London news from Crystal Palace.
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Thank you all for your suggestions - Something else I might try is to turn down the gain on my rooftop aerial amplifier - It occurs to me that I wasn't getting this problem before switchover and the digital power ouput was increased. The Triax amp gain is currently set on max (around 22 db I think) So perhaps I can reduce the sensitivity towards the other more distant transmitters and just home in on Crystal Palace. Interesting problem though - I wonder if anyone else is experiencing this overlap?
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Kevin. I did wonder if it might need a tweak - but since it's attached to the top of the chimney, I will only try it as a last resort if other suggestions fail to cure problem. I think the aerial still "sees" CP as the prime transmitter because traditional channels (BBC1, 2, ITV1, CH4 & 5) are still all "London", so perhaps a retune will only juggle the other channels? Can but try it in May! Thanks again.
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I've been reading with interest the problems others are experiencing with their Freeview reception and it prompts me to ask a few basic questions:
First, I presume that transmitters are mounted on tall masts so as to ensure the signal emitted is presented with the least obstruction over the greatest possible distance - but what is the profile (shape) of the signal? Does it start off narrow and spread out wider with distance?
I note that several of the people with reception problems are quite close to the Crystal Palace transmitter and I understand that sometimes this might result in the signal they are receiving being too strong and requiring attenuation - but given the height of the mast, is it also possible to be so close to the transmitter that the signal passes over the top of a roof mounted aerial and hence misses it completely?
Finally, I live around 25 to 30 miles from CP and receive excellent freeview reception via an indoor aerial - obviously, the signal has to pass through the walls of my property - so why would something like leaves on a tree disrupt reception?
Thanks in advance.
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Mike, Thanks for your detailed explanations and answers to my questions - the null filling and beam tilting is most interesting - I guess there must be an optimum distance between the transmitter and the horizon where reception is just about right. Not too close and not too far. So neither attenuation nor booster needed.
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Monday 18 July 2011 3:51PM
I live in Sevenoaks, Kent and get excellent Freeview reception on all channels from Crystal Palace. Occasionally I experience picture and sound breakup when the weather conditions are set fair (high barometric pressure) which I think is due to the "inversion" effect. Currently, when this happens I simply switch to analogue. However, after switchover next year, analogue will not (of course) be an option. Do you expect the inversion effect to still be a problem after switchover?