Message-ID: <000101c193d2$e7f08780$23677ad5@default>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: "LF-Group" <rsgb_lf_group@blacksheep.org>
Subject: LF: Phase meter
Date: Wed, 2 Jan 2002 20:27:13 -0000
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Hi Paul
 I have been wondering about that for some time and was hoping a souncard
version of the Loran program that Peter G3PLX was experimenting with might
appear. I would dearly like to confirm my thoughts about the path across.

If you look at some of my early CFH plots (Sept- Dec 2000) you can see the
strength rise to a peak just as the shadow at ground level reaches a point
about 1000kms east the Nova Scotia coast. (This is just less that an hour
before sunset, and would tie in with the recent of signal acquisition
reports)  By doing a little crude geometry I reckong that at this time the
shadow at 100kms altitude has just reached mid-Atlantic. The signal level
decays again then and rises again (to a much higher level) as the shadow at
ground level reaches the Nova Scotia coast. At that time I think the shadow
at 100kms altitude is at about 3/4 of the path. That is just the point where
we need a 'reflection' for two hop propagation. The reasoning is very crude
but could be confirmed by watching the phase change as a function of
increasing path delay. What I am not sure of is the level of frequency
stability that would be needed at the TX end. I suppose slow drift could be
'calibrated out', maybe by monitoring a station locally, inside ground wave
distance.

I think all the information is there in the samples taken for waterfall
displays, but is not used (??) . I think you might have to talk nicely to
Wolf...... it would fit well with his logging facility in SpectrumLab, that
Brian CT1DRP uses for his plots of DCF39 (and other slots). In fact it is
such a comprehensive piece of software it may already be there!! There are
many parts of Wolf's program that I have not had time to investigate.

Cheers de Alan G3NYK
alan.melia@btinternet.com