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Date: Sun, 09 Sep 2007 20:16:15 +0100
From: John Andrews <w1tag@w1tag.com>
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Subject: Re: LF: Dual mode data test QPSK31(503.2) + PSKAM10 (503.1)
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Graham,

> According to  the 'printed word' the PSKAM10 mode is supposed to  be 
> quite robust .. 

The printed word is correct, at least to a point. PSKAM10 (only 
available in F6CTE's MultiPSK program)is definitely more robust than 
straight PSK31. This comes less from the lower data rate than the 
transmission of each character twice. It takes up less BW than straight 
PSK31.

Its biggest shortcoming appears to be in establishing initial decoder 
sync. Sometimes, during a fade, the decoder will go "on walkabout," and 
not re-sync for some time. That can be a bit annoying. Patrick suggests 
that his PSKFEC31 offers better decoder sync behavior.

I have run PSKAM10 on 137 kHz a number of times, both at full power and 
in low power tests over a 200 km path. Jay and I have had several QSO's 
in this mode, and it has been well behaved. The mode's noise behavior is 
much better than straight PSK31.

Interesting alternatives would be the PSK08 mode in Spectrum Lab, and 
JASON Fast. I'm looking forward to seeing how some of these things work 
with the more rapid fading at 500 kHz.

Hopefully, someone will give your PSKAM10 beacon a try, and report the 
results. The MultiPSK program may be downloaded at 
http://f6cte.free.fr/index_anglais.htm .

John Andrews, W1TAG