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Old March 30th 18, 07:16 PM posted to
Bill Wright[_3_]
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Posts: 2,448
Default Crystal Palace Issues

On 30/03/2018 14:36, John wrote:
I dutifully retuned, and was shocked to find a load of channels missing! Especially annoying was the loss of BBC News HD and BBC Four HD.

I live in a Central London tower block and have my own Group A aerial pointing at Crystal Palace/Croydon at rooftop level and a 70m cable run down to my living room.

The obvious thing would be to remove the existing Group A aerial and replace it with a Group W one. However, I worry about its lesser sensitivity at the Group A end.

If you are in central London you will be swamped with CP signal, even
allowing for beam tilt (tx looks downwards a bit).

The rooftop is so high (effectively the 22nd floor) that I fear
interference from Bluebell Hill and Hannington. Is this something that
I ought to fear in the era of DTT? Or could it mean being able to see
local news from different areas?

No they don't use the same channels except for the new 55/56 allocation,
and you can't do anything about that.

Is an alternative getting a Group C/D aerial and combining it with the existing Group A? Advantages/disadvantages?

Just don't.

I see from my Humax PVR that it sees no signal whatsoever from 55 or 56 from the existing Group A. I am not surprised.

Your 70m cable will lose more on the higher channels, especially if it
has rubbed anywhere and got a bit of damp in it. That could easily
explain the problem.

The CP signal will be so strong that the aerial could well be faulty and
still provide enough signal to seem OK. But that would show up on 55/56.

Are you sure there isn't a Gp A filter anywhere, fitted to stop 4G problems?