[pskmail] Re: Various subjects

  • From: John Douyere <vk2eta@xxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Fri, 8 Jan 2010 07:53:19 +1100


I can't reproduce this issue with the latest version of Fldigi
(3.13BN). I remember seeing this in the initial developments but I
know that Dave improved the squelch handling for psk modes (all
flavours) before the pskr release to alpha.

I tried both ways between two laptops under Ubuntu (one running Hardy
one Jaunty) with noise added to the signal and I can't see this.

On the other hand something to look at maybe could be the calibration
of the squelch value. If you look at the psk.cxx code you will see
that for pskr modes we multiply the squelch value by 4 to make up for
the extra sensitivity of the mode, otherwise the squelch cuts out good

        // FEC: adjust squelch for extra sensitivity.
        // Otherwise we miss good characters
        if (_pskr) {
                metric = metric * 4;
                if (metric > 100)       metric = 100;

Also, for reference, I set the squelch threshold at about 1/5th of the
total squelch indicator.

Hope this helps Rein,



> I now have an issue with PSK500 decoding. PSK500 needs a preamble of
> 'XXXXXX' to decode the start of a packet. I see the squelch bar dive down to
> zero and then build up when the packet starts.... After going through fldigi 
> code for 8 hours
> I have found no difference so I wonder if somebody else sees this.
> 73,
> Rein PA0R

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