Hi James, At this QTH the problem is definitely at the computer output and *not* at the SDR1K itself.
I determined this by monitoring the soundcard's output with two channels of an oscilloscope while observing the RF envelope of my transmitted signal on a third channel. In CW mode, the soundcard's outputs normally have a nice 90 degree phase relationship. However, when I observed the screwy RF envelope, this 90 degree relationship was lost, and the resultant phase relationship between the two signals could be anything. The erroneous phase shift was often much greater (in degrees) than one would expect if the soundcard was one sample out-of-sync on either channel (at 96 ksps such a slip would result in a delay shift of only 10 us - I had my scope set to 2 ms per division, and so such a small delta would have been imperceptible to me). My gut feeling is that it's the software. Otherwise, I would expect to experience the same problem when running sideband. But I ran an experiment yesterday in which, while transmitting LSB, I monitored the USB side of my signal with a seperate receiver, and I never heard a change (nor saw a change on the other receiver's s-meter) in the level or quality of the USB signal. I cycled from receive to transmit at least 100 times, and all appeared fine. - Jeff, K6JCA -----Original Message----- From: James Courtier-Dutton [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 24, 2006 2:22 AM To: Jeff Anderson Cc: Lee A Crocker; FlexRadio@flex-radio.biz Subject: Re: [Flexradio] Has anyone seen this CW Transmit problem? Has anyone been able to narrow down the problem to the computer soundcard output, or is something going wrong inside the SDR1000 hardware. This problem could be happening in the computer software or the sound card hardware, but identifying which part is wrong would be helpful. There have been cases of some sound card hardware causing the left and right channel to be one sample out of sync. James _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
