A rough and ready explanation could be that modes which rely on phase are degraded when you compress the TX signal (ALC displayed) - for phase modes you must transmit a 100% clean signal, much more important then signal strength.
Simon Brown, HB9DRV http://sdr-radio.com From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com] On Behalf Of Andy obrien but.. I think the original question also asked about modes other than PSK31, what about them? JT65A, for example is not a mode that once has to watch ALC so much. Does anyone have a good easy to understand description of why ?
