Hi Hugh, yes I supose it would have some effect. The advantage is that all
the transmitters are under "atomic" control so there is almost a continuous
phase difference between their carriers. The "mush" area, I think, refers
mainly to the reception and demodulation of the AM program material. I
suppose within ground-wave range there is "beat" when the strengths from
Droitwich and say Westerglen are approximately the same ....the beat
frequency would not more than 0.00001Hz or about 1 cycle in 30 hours (I hope
my thumbnail calcuation is right....but I sure someone will tell me if it
isn't). I dont expect that would give much problem but the path differences
from the different tranmitters might give some interesting effects at
distance. The only person I know who does monitor R4 is Laurence in
Anchorage.
Cheers de Alan G3NYK
[email protected]
----- Original Message -----
From: "Hugh M0WYE" <[email protected]>
To: <[email protected]>
Sent: 12 August 2003 16:21
Subject: LF: Re: BBC R4 LW "Frequency Standard"
Hi Alan, Group,
Interesting article about BBC R4 LW.
Does the fact that there are multiple transmitters on this frequency have
any bearing on those who might use the 198kHz signal as a propagation
indicator outside of the UK ?
Presumably the interference pattern ("mush area") extends way beyond our
shores, and someone monitoring, say in the 'States might receive a weak
signal, not because there was no propagation, but because the two
transmitters happened to be in cancellation.
I assume the signals that we might use for reference, such as DCF39, have
only one source.
73
Hugh M0WYE
----- Original Message -----
From: "Alan Melia" <[email protected]>
To: "LF-Group" <[email protected]>
Sent: Tuesday, August 12, 2003 3:57 PM
Subject: LF: BBC R4 LW "Frequency Standard"
> Hi All, I have posted the latest DTI Time & Frequency Club Newsletter to
my
> web site. It contains a short description of the frequency control of
the
> BBC Radio 4 Longwave transmitters on 198kHz, together with details of
the
> phase modulation data service it also carries on the carrier. This will
be
> interesting information for those of you who, like me, may have a 198kHz
> off-air standard in your workshop.
>
> Download of the 68kB pdf file is available from the link in the contents
> section on the index page.
> http://www.alan.melia.btinternet.co.uk/
>
> Cheers de Alan G3NYK
> [email protected]
>
>
>
>
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