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Re: LF: Phase meter for propagation experiment

To: [email protected]
Subject: Re: LF: Phase meter for propagation experiment
From: "James Moritz" <[email protected]>
Date: Fri, 12 Apr 2002 11:18:34 +0100
In-reply-to: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Dear LF Group,

Thinking a little more on this idea, it seems to me that using LF standard frequency signals as a phase reference has a basic flaw - the reference phase signal received at the stations taking part in the experiment will also be affected by LF propagation phenomena - there would be no easy way of separating the effects of propagation on the signal being studied from propagation effects on the reference signal. So it would seem to be essential to use a reference signal independent of LF propagation effects, such as GPS or the TV line timebase.

Thanks to DJ8WX for the LF broadcast info - looking at the Droitwich signal with my vectorscope circuit some time ago, the 198kHz carrier appears to be phase modulated, but the phase deviation is only a few 10s of degrees; the carrier phase just wobbles around a mean value, which would not matter much in a measurement integrated over several seconds. Some of the other European broadcast stations have similar phase modulation.

Cheers, Jim Moritz
73 de M0BMU



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