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Message-ID: <3.0.6.32.19990929121029.0080d100@mail.dlc.fi>
Date: Wed, 29 Sep 1999 12:10:29 +0300
To: rsgb_lf_group@blacksheep.org
From: =?iso-8859-1?Q?V=E4in=F6_Lehtoranta?= <vaiski@dlc.fi>
Subject: Re: LF: re Vaino's rx findings and my thoughts
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Dear friends,

Your comments, especially that of Alan, G3NYK, were
much appreciated. Having been a professional monitor
for last 40 years this AR-7030 Plus was my first
investment for 'own' receiver. It really was worth it.
In a correspondence with AOR folk I stressed the point
that I'm only interested in copying weak signals among
noise. I wrote a couple of articles about the subject
for the SRAL magazine "Radioamatoori" some years ago.

There have been during the past decades most commercial
receivers available, including Collins, Racal, R&S,
Watkins Johnson etc. Most of them have not been designed
for 'weak signal' monitoring but for routine monitoring.
A number of ham receivers or transceiver are much more
suitable for contesting and receiving weak noisy signals

In case someone else is interested, let me refer to the
doctoral thesis of Peter, SM7CMY with a title:
'Signal Detection in Noise with special reference to
telegraphy', University Hospital Lund, Sweden, 1994.

On the subject of Ionospheric Cross Modulation (ICM)
it was interested to observe Russian FS ICM modulation
on both DCF39 138.83 and DFC49 128.93 kHz, most probably
caused by 1386 kHz which is located at Kaliningrad area.
We have a complete listing of observed ICM cases on LF/MF
collected in connection with routine EBU LF/MF monitoring.
These monthly BC band observations cover years 1967-1992.
The number of observed individual ICM cases is around 120.
To identify the real cause and source for 'extra modulation'
is in itself one of the most difficult monitoring task.

73 to all from Vaino, OH2LX
IARU Region 1 Auroral studies coordinator

----------------------------------------------------------
V.K.Lehtoranta, OH2LX, POBox 50, FIN-05401 Jokela, Finland
------ Tel: +358-9-4173965 ---- Fax: +358-9-4173961 ------
E-mail: vaiski@dlc.fi - alias: oh2lx@dlc.fi & oh2lx@sral.fi