Crystal Palace - Freeview HD reception.

Michael Chare

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Mar 11, 2011, 6:15:59 AM3/11/11

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The BBC HD channels are transmitted from Crystal palace on channel 31 at
half the power level of the SD channels.

I live in a marginal reception area, and whilst I can receive 4 of the
Freeview muxes perfectly, the mux on channel 32 has a low quality level, and
the mux on channel 34 is useless most of the time.

Is there anyway of determining whether I can receive the HD channels OK
other than by acquiring a suitable receiver, or using the services of an
aerial installer.

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Michael Chare

ne...@address.invalid

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Mar 11, 2011, 6:53:34 AM3/11/11

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You could start by giving us details of your existing aerial system.

Mark Carver

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Mar 11, 2011, 8:35:15 AM3/11/11

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The HD mux being half power (only 3dB down on the SDs) is not the prime
consideration.

More significantly the radiation pattern is not omni directional, and
the allocation has four interference sources. BBC 1 analogue from Sandy
Heath and Rowridge, plus a DTT mux each at Reigate and Bluebell Hill.

The combination of those above factors, reduces the range and robustness
of the HD mux.

First check, stick your postcode into this, and ensure you tick the
'Aerial Trade' box

http://www.digitaluk.co.uk/postcodechecker/

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Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

Michael Chare

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Mar 11, 2011, 3:15:04 PM3/11/11

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--
Michael Chare

"Mark Carver" <mark....@invalid.invalid> wrote in message
news:8tumoj...@mid.individual.net...

I live near Sevenoaks, the above checker shows 'variable reception'.

In general the checker is a bit conservative (apart from mux 34 where
something odd is happening. My Toppy shows the signal quality varying
between about 5% and 90% and I usually don't get a usable picture. I have
seen in working OK though.)

Brian Gaff

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Mar 12, 2011, 3:51:20 AM3/12/11

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Maybe you need to talk to a few neighbours and see if they have already done
the same and what they ended up with?

It very much depends on why the signal quality is bad, ie is it your
existing installation, multipath, just weak signals, interfererence from
another transmitter or what.
If its just weak then one can improve it with a better installation.

Brian

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Brian Gaff - bri...@blueyonder.co.uk
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Michael Chare" <Munders...@chareDOTorg.uk> wrote in message
news:SPCdnY_CPLvzmefQ...@brightview.co.uk...

Mark Carver

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Mar 12, 2011, 5:05:21 AM3/12/11

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Michael Chare wrote:

> I live near Sevenoaks, the above checker shows 'variable reception'.

> In general the checker is a bit conservative (apart from mux 34 where
> something odd is happening. My Toppy shows the signal quality varying
> between about 5% and 90% and I usually don't get a usable picture. I have
> seen in working OK though.)

I'm pretty sure the main lobe of the HD mux is north from CP towards Central
London, so you're certainly not in a favourable position. The problems on the
mux on Ch 34 could well be co-channel interference from the BBC Mux at
Heathfield. Your aerial will also be looking straight at Sandy Heath, and
receiving BBC 1 analogue from there on Ch 31. However, the good news is that
transmission ceases on April 13th at Phase 2 of Sandy's DSO. After that date,
there will be no more radiation of Ch 31 from Sandy. It'll be interesting to
see whether that does make the CP HD mux receivable for you.

(BTW, I was wrong in my last post, there are no transmissions, digital or
analogue from Bluebell Hill on Ch 31)

Michael Chare

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Mar 12, 2011, 8:15:57 PM3/12/11

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Thanks.