Rein, 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 characters. // 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, Regards, john > 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 > > >