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Message-ID: <5.1.0.14.0.20020807101505.00a86448@gemini.herts.ac.uk>
Date: Wed, 07 Aug 2002 10:40:40 +0100
To: rsgb_lf_group@blacksheep.org
From: "James Moritz" <j.r.moritz@herts.ac.uk>
Subject: Re: LF: Jason Testing
In-reply-to: <01C23DEC.40300420.g4jnt@thersgb.net>
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Dear Andy, LF group,

Thanks for the tests - I received the G4JNT Jason beacon last night for a 
few hours. With a loop antenna aligned on Andy's QTH , the signal started 
off as "nearly audible", and strong enough to produce full quieting on the 
Jason waterfall display. So as a crude test of low SNR conditions, I turned 
the loop until the signal was almost nulled out, and copy was marginal. 
Under these conditions I found the KK7KA decoder produced consistently 
fewer errors, corresponding to an advantage of a few dB, I suppose. I found 
that a signal that would be "M" copy viewed as 10s/dot QRSS would give 
almost perfect copy (a few % of corrupt characters) using Jason with the 
KK7KA decoder. I also found that my old P133 computer gave results 
consistently a few dB better than my newer laptop - this was true both with 
Jason and with the Spectrum Lab waterfall display, so would seem to be due 
to the different sound card hardware rather than any software issue; worth 
investigating further. As it got dark, the noise level rose by about 20dB, 
so by the end of the session, I had to gradually turn the loop so it was 
lined up with G4JNT again to get good copy.

Cheers, Jim Moritz
73 de M0BMU

At 08:27 07/08/2002 +0100, you wrote:
>I will be transmitting another Jason test transmission at low power tonight
>  137.500000 kHz < 500uW ERP.  Start time at least by 1900z, and probably
>earlier.
>
>Andy  G4JNT