When I originally set-up my Flex for PSK using DM780, I played with it with a local ham and we both noted that we each saw sidebands. We went through all the normal checks with our sound drivers and any and all the normal checks one would go through with double checking gain settings in the signal chain. All seemed well, and got no sidebar comments. until someone had the guts to say something to me today. I use DM780 with HRD 5.0, VAC and vCom.
Today, someone came back and e-mailed a couple of screenshots of my PSK31 signal when I was operating at 14.070. Sure enough, a problem. But these were not the normal sidebars, but rather harmonic signals about 125 Hz off on either side of my main signal. Then I had a later QSO, about 1000 Hz higher in the waterfall and the problem disappeared!!!! I have noted that sometimes, I do get two bigger harmonic bumps on either side of the transmitting frequency in PowerSDR which appear quite close to the transmitting frequency. I can't predict when this will happen. I tried it again a bit later at the same frequency and I couldn't recreate this. I will be when I see these larger close in harmonics, this is when I get the "extra" signals being transmitted that others can see. I do have the screenshots still. I have noted that I do see more harmonics on my signal when I am operating in the lower half of the waterfall when operating on DIGU or DIGL. (Of course, when I am in DIGL, it looks "reversed" in the Panadapter as one would expect, since the lower frequencies are toward the carrier.) So where is the most likely culprit for these large harmonics that cause this problem of duplicate signals 125 Hz off; The transmitter or something in the audio chain? And why do I tend to see more harmonics when I operate in the lower part of the waterfall closer to the carrier VS the upper? There may be two different issues. They may be related. I am at a loss. Scott AC8DE _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ Message delivered to [email protected]
