Well, I heard about CMSK a few days ago and downloaded the program. Initially I had ZERO luck with decoding anything with it BUT part of that was NOT a lot of CMSK signals on the air hi hi
I got on CMSK on the 11th of August and called CQ numerous times on 30mtrs (10.141) and SOMEONE did come back to me. I could not decode the station at all. I tried tuning him in several times, fine tuning, and playing with the Sample Rate. Finally gave up and typed in a message saying that IF YOU ARE COPYING ME QSY TO CONTESTIA 8/250 I switched to contestia and it turned out to be VK3XQ, Rob, who had been answering my call. He copied my CMSK CQ without a problem. We didn't have much time to try much else at that time so a 2 way QSO was not achieved. Today, I ran into Phil, KA1GMN, on 10mtrs on Olivia mode while I was on my Flex 1500 rig (SDR). Phil had some time so I switched to my Analog rig (FT-100D) and fired up CMSK and we tried CMSK63. After almost giving up - I started again playing with the SampleRate settings and FINALLY started getting a docode!! By using Phil's signal I finally got perfect copy with a samplerate of 8062. We chatted for about an hour with near perfect copy. Nice mode once it is set up properly. The CMSK program would not work with my Flex 1500 and the Virtual Audio cables - so for now I am using my FT-100D with my SignalLink USB interface. I had used CheckSR program to see how far off the SignalLink USB was several times in the past. It showed both transmit and receive was about -14 cycles off. However, the CMSK program did not start decoding perfectly until I set the SampleRate to about 8062. This, on the surface at least, does not correlate with the CheckSR prog used on my SignalLink BUT the 8062 setting works for me - at least with Phil ... So, it looks like soundcard calibration will be extremely critical for using this mode successfully. I'm really appreciative to Phil, KA1GMN, for his help and his time! ---Gary WB8ROL
