Dick N3HKN "I have considered Huff & Puff VFOs, and have the parts on-hand, but I keep coming back to a DDS type solution for the SDR." You wrote.
The General Coverage idea comes with the DDS idea and the now interest in micro wave PLL chips. There are kits and some are really good on price. $38 is ok for this type of PC/Radio technology. You really can't buy a good VFO for that price. There however are no H&P kits at this time. But they are not far from being so. I think the H&P circuit will be very useful but in a limited way. Mostly to use with existing receivers i.f. sections as an add on QSD with passband tuning of perhaps 1 MHz via an accompanying H&P VFO. Truthfully you can have the LO IN in this scheme as a fixed crystal like SR 40 does. Interest in the H&P and use then by more people will lead to innovations with it in time. Mostly to see what can be achieved in addressing the spurs. But the spurs can be worked around in some SDR softwares that have a built in notch filter. CIAO has such a notch filter. I did run into quite a few people building the H&P from this group here and so they are out there now. About 20 joined on at once. One fellow had recently re~invented it into a "phase shift comparison loop" borrowing on phase shifting ideas from here. I think he was mixing the clock and the divided down VFO, in a XOR gate, and then to the Varicap. It seems interesting to try. I am a little vague on his idea but have his circuit here someplace. There might be a thing or two more in the circuit I am forgetting. I recall it was simple. There was I think, a phase splitter in it somewheres. * Yesterday I confused my spectrum dislays and gave a -80 dB figure for the the SDRadio display when it is on the CAIO that I have -80 dB on extremely loud signals. Yet SDRadio seems 6 to 9 dB louder by comparison. Both are extremely sensitive compared to my solid state radios and surprising. The sound cards then have allot of gain in them. www.danssmallpartsandkits.net <http://www.danssmallpartsandkits.net> Above is a good place for semicondutors, lots of different FETs, toroid cores, IC's, 1/4 shaft reduction drives, variable capacitors, i.f. cans, coils, etc. Pretty much everything. Even .001 uF feed through capacitors. I noticed that there are balanced mixers also: SBL-1, etc. He has a special on IC's but I have not been back yet to check that page out. This place takes money orders and has info on how to order by mail. _____________________________________________________________________ PrivatePhone - FREE telephone number & voicemail. A number so private, you can make it public. http://www.privatephone.com Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/soft_radio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> 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/
