While we are on this interesting subject of sound card calibration I have a question in regards to the effect of the calibration itself on the capability of properly decoding the signals.So two questions:
1. I noticed that although most PSK31 signals I receive are showing the two phase positions as displayed on the scope at 180 degrees, some are consistently at less angle than that, typically down to about 135 degrees. When I say consistently I mean it is obviously not just a momentary shift due to propagation as one can see with DX or QRMed signals. Is this related to the difference in calibration between the sound cards? 2. In the case of PSK31 how much does mis-calibration really affects the reception? Does it result in a simple an increase percentage of mis-decoded characters when propagation/QRM creates unwanted phase shifts? 2. Which modes are the most / least sensitive to sound cards calibration differences? My guest is that in the least category we should find the psk and ifsk (e.g. Domino) modes and in the most sensitive category MFSK modes. Is that a correct assesment? Thanks, John (VK2ETA)
