Walter and Larry, I had serious image rejection problems with my factory-built Elektor SDR. It turned out that P5 on IC1 (74AC74) had no signal because it was shorted to ground. The output from channel 2 was much lower than the output from channel 1. The short was somewhere on the pc board where the IC holder is attached. To fix the problem,
1) I cut trace between P5 on IC1 and P6 on IC2. 2) I pulled P5 of IC1 from the IC holder. 3) I connected a wire between P5 of IC1 and P6 of IC2. Ugly, but it worked. To see if this is your problem, I recommend downloading Peter's G8JCFSDR program. His software makes it easy to see whether you are getting proper signals from the Elektor board. By the way, I emailed this problem and solution to Elektor, but they did not reply. Hope this helps. 73, Gus, N1CCW -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Larry Robison Sent: Sunday, October 28, 2007 2:29 PM To: [email protected] Subject: Re: [soft_radio] elektor sdr mirror frequency rejection Walter, Interesting! I have noticed exactly the same thing on the Soft66DB2 receiver from Japan. I did the image rejection adjustment and that did not help. After checking all of the things that you did, I purchased an M-Audio sound card thinking that the better sound card would solve the problem. NADA! Any ideas would be welcome here also! Thanks to all and especially you Walter for bringing it up before I commit hari kari! --Larry W8ER
