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Message-ID: <5.1.0.14.0.20020218121805.00ab3410@gemini.herts.ac.uk>
Date: Mon, 18 Feb 2002 13:06:59 +0000
To: rsgb_lf_group@blacksheep.org
From: "James Moritz" <j.r.moritz@herts.ac.uk>
Subject: Re: LF: M0BMU test transmission on sunday evening.
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Dear Markus, Wolf, LF Group,

Thanks to all the stations listening to the PSK08 test last night, and for 
all the reports received. DF6NM and myself were able to have a QSO lasting 
about half an hour with a lot of info exchanged and almost perfect copy on 
both sides. I was quite impressed with this, since I could not really hear 
Markus' signal at all in the headphones under the QRM; maybe a more expert 
CW operator than myself could have heard something, but certainly not have 
been able to carry on the leisurely QSO that we had. Conditions were not 
ideal at my end with the local noise level, and I was using lower ERP than 
for the TA tests, with my antenna at a lower height.

I think PSK08 could form a good basis for development of a specialised LF 
data mode; the bandwidth is suitably narrow, and it can clearly function 
with the kind of SNR we experience. At the same time, the speed of 
signalling is probably as fast as in a manual CW contact at moderate 
speeds, as is the norm on LF. The band conditions at my QTH were noisy, but 
with few QRN crashes - the static crashes seemed to be what caused the 
occasional corrupted character, so a developed version might attempt to 
improve on this - perhaps using some form of error correction; or a 
hardware or software noise blanker might be helpful.

So congratulations are due to DL4YHF; SpecLab may be a "building site", but 
it is one with an ever increasing number of interesting features and 
capabilities, and well worth taking the time to investigate. Btw Wolf, I 
didn't know there was such a thing as a "squelch killing postamble tone", 
so my hardware may be ignoring it - what form does it take?

Cheers, Jim Moritz
73 de M0BMU