Hi Eric, I assume you're talking about the softrock-40, although it's not specifically mentioned in your email.
It sounds like you have absolutely no image rejection at all.....which probably means you aren't sending I and Q to the sound card. If the sound card is getting only I (or, only Q), you have no way of knowing except that there is no image rejection at all-like ZERO db difference. There is the possibility of overdriving also, this creates the same problem with a digital signal as it does with an analog one-gross non linearity which could account for signals not appearing to be rejected properly...not sure it would cause your symptoms though. Some others might comment on this. Is there a possibility you're trying to run it on a laptop? Many of them only have mono inputs. Having a malfunction in the timing (counter) or having one of the switching phases missing would account for the problem too. Have you checked the timing of the input signals to the analog switch to make sure they are all switching and that they're in the correct phase? If you have a scope, check the phase of the signals being fed to the analog switch (and/or) that one of the signals is missing and/or stuck low/high. If you have only a frequency counter, you should find 1/4 the clock frequency on each of the pins to the analog switch. If you don't have a scope or counter, remove the xtal and hook a switch (with a debounce R/C network) to the crystal socket. This allows you to clock the counters manually and to confirm that each input to the analog switch is moving in the correct phase relative to the other inputs. The transformer wiring is not the problem unless you wound your transformer differently than the instructions say. You might check to make sure the wires leads from the transformer are soldered to the board correctly (in the right holes), an error here wouldn't necessarily show up because the turns ratio of T1 is close to 1:1, so there might not be a big signal loss if this was done...so it might have good audio output levels if there was a problem with the connections to the PCB being scrambled. Regarding room on the PCB to experiment.....the board is the business end of the receiver. Except for the front end tuning components, there is little to experiment with. The only exception might be with the front end tuning components if you want to move it to another band. To make it multiband, you would probably need another complete PCB anyway. As far as the board goes, there is little to tweak or adjust, on the board, I'm not sure what purpose a larger board would serve. GL to all. Art At 07:06 PM 9/20/2005, you wrote: >The radio went together fairly easily, though I'm at a >loss to figure out why an experimenter's radio is >jammed onto such a small board. This might be OK for a >production rig, but some room would be nice to >experiment. > >That said, the radio works except there is no image >rejection and the DSP image rejection controls do >nothing. The instructions say, "If the image cannot be >nulled at least 50 db, then a problem exists..." Well, >some guidance would have been helpful. Especially, >given my opening criticism. > >I am reluctant to tear into this think quite yet as >there is not a lot of room to work. I'm kinda thinking >it may be a transformer mis-wiring on my part. Again, >we're talking an experimenter's radio on 40 meters >where things are relatively less critical than other >bands, so a little larger toroid with more room to >make changes would make it a lot easier. > >I'm hoping when I fix the image problem that all that >7.056 +/- 5 khz energy is going to at least be >diminished. 7.056 is S5. 7.051/7.061 are S3. > >Anyway, I have no doubt the problem is my error. I >just want a little direction so that I can minimize >stress on the board. > >Eric >KE6US >www.ke6us.com > > >__________________________________________________ >Do You Yahoo!? >Tired of spam? Yahoo! Mail has the best spam protection around >http://mail.yahoo.com > > > > >Yahoo! Groups Links > > > > > > > > > > >-- >No virus found in this incoming message. >Checked by AVG Anti-Virus. >Version: 7.0.344 / Virus Database: 267.11.3/107 - Release Date: 9/20/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.11.3/107 - Release Date: 9/20/2005 ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
