[pskmail] Using MFSK modes

  • From: "Rein Couperus" <rein@xxxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Fri, 12 Aug 2011 10:12:52 +0200 (CEST)

The mode table in pskmail contains PSK, MFSK and THOR modes.

I have been able to monitor quite a number of qso's during the last few days,
and it becomes clear there is a problem with MFSK.

The effect is that when the mode is degraded from PSK250R to MFSK32, 
one of the stations (server or client) clearly does not decode the MSK32 signal,
and after a few retries the mode falls through to THOR22.

After the link gets better (pactor qso on top of the connect finished), the 
server tries to 
upgrade to MFSK32 again, but that does not succeed, so the server stays in 

After seeing this also on my own connects, I did some tests, and it turns 
out that most of the time the slight frequency difference between server and 
is probably the cause. The same happens with MFSK16 and THOR8...

I am thinking about removing the MFSK modes from the table. That 
is a pity, because the MFSK modes are the most sensitive... but that 
does not bring any advantage if the smallest frequency difference defeats it.

* Did you also see this effect?
* Would you be in favour of dropping the MFSK modes?


Rein PA0R


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