Message-ID: <000c01c36108$3e28cdc0$6507a8c0@Main>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
References: <000e01c360e2$114c6300$6507a8c0@Main> <000701c360e6$157157c0$3704210a@Hugh>
Date: Tue, 12 Aug 2003 20:30:48 +0100
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Subject: LF: Re: Re: BBC R4 LW "Frequency Standard"
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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
alan.melia@btinternet.com

----- Original Message -----
From: "Hugh M0WYE" <m0wye@thersgb.net>
To: <rsgb_lf_group@blacksheep.org>
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" <Alan.Melia@btinternet.com>
> To: "LF-Group" <rsgb_lf_group@blacksheep.org>
> 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
> > alan.melia@btinternet.com
> >
> >
> >
> >
>
>