Can anyone tell me just how much (or little) sound card calibration affects PSK and RTTY reception? Here's my reason for asking:
When I got my current sound card, the first thing I did was to run the various calibration routines from MMTTY, DM780, and MultiPSK. These calibration routines showed the card was off by 181 parts-per- million. I set up the various software accordingly and all was well. I just started noticing reception problems, primarily on RTTY and ran another set of calibrations. This time, results showed the card off by 6984 parts-per-million. The size of the error doesn't worry me too much, as it is still under 1%, and I can only "assume" (hope?) that the calibration changed as the card "burned in". Going to monitor it closely to see if it changes any more over time. Could this much of an error cause trouble decoding RTTY signals if not compensated for in the software? Even with a strong signal I was losing quite a bit of text, although PSK decoding seemed to be totally unaffected. Thanks in advance 73 Dave KB3MOW
