Envelope-to: dave@picks.force9.co.uk
Delivery-date: Fri, 02 Dec 2005 16:50:04 +0000
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From: "Alan Melia" <alan.melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
References: <003001c5f759$05b2c880$f500a8c0@Dell5150>
Date: Fri, 2 Dec 2005 16:39:06 -0000
MIME-Version: 1.0
Subject: Re: LF: loran c closure
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Hi Dave I dont think its the phase mod that is creating the "Dalek effect".
I think this is more likely to be interference between the two signals.
Westerglen is not "controlled" (should be "measured" really) by NPL though
it does have a rubidium source. Could the Dalek effect be due to the time
delay in the program modulation reaching Scotland there must be up to about
a millisec. That means there is only very slow fading as the carrier phase
difference is fairly constant but the mod is out of phase and beating. I
know the wide area quasi sync PMR systems beloved of Pye-Philips (and
laterly Simoco) used to have audio delay lines for equalising the delay
between sites, as well as ovened crystal reference standards (the old
HS400).

Cheers de Alan G3NYK


----- Original Message -----
From: Dave Pick <dave@picks.force9.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: 02 December 2005 15:56
Subject: RE: LF: loran c closure


> That phase modulated data is a real pain. In the Scottish borders
Droitwich
> beats with Westerglen (between Glasgow and Edinburgh) which either doesn't
> have phase mod data, or has different data on it. The net result sounds as
> if the Daleks have taken over radio 4. Surely there are better ways of
> signalling to electricity meters or whatever it's for?
>
> Dave G3YXM.
>
> -----Original Message-----
> From: owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Johan Bodin
> Sent: 02 December 2005 11:14
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: LF: loran c closure
>
> Warren,
>
> >   BBC 4 from Droitwich on 198 kHz  is kept in very close tolerance by
the
> NPL.
> > http://www.npl.co.uk/time/droitwich_bulletin.html
>
> Yes, but it is not so easy to use "right out of the box" because it has a
> lot of phase jitter (intentional PSK) that has to be smoothed out.
>
> 73
> Johan SM6LKM
>
>
> --
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>