There are a couple of circuits using a PIC16F84 or a PIC16F628 for a Huff and Puff VFO
http://www.ik3oil.it/_private/article%20FLL%20VFO.PDF http://www.qsl.net/om3cph/counter/lcd/contribs/pic_flck.htm I am currently building the second one, I just have to build the extra circuit board and reprogram the PIC for it, I already have the frequency counter part built, tested and installed in a cabinet I plan on using it with a 5-5.5Mhz VFO and a AD9850 DDS in place of a bank of crystals for a 9 band hetereodyne LO ... another experiment for this Winter is AD9850 DSS and 9 VCO's (one for each Ham band) with a 1:1 phase comparator and PLL ... in other words the output of the DDS would be exactly the same frequency as the VCO for the band you want, if that works then I'll expand it using 6 octave VCO's to cover the BCB through 30Mhz for a continous coverage receiver JR --- In [email protected], "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > > Recently I have been building and testing my Dual Gate FET QSD idea. > I am not finished yet but one thing I was warned about was IMD. So I > decided to try a Class A bias scheme and later I will check the > harmonic distortion and other needed testings. Anyways I will continue > to build it and then see if there is a way to over come any IMD. I am > hoping Class A is the approach. I have one FET section built on the > same breadboard as I have been building a Huff & Puff VFO. The Fet I > am using can output enough power to directly feed the sound card. > > So far I have tested it for good sine wave reproduction from 1 to 30 > MHz and it passes that, next I need to test it with square waves. > > If in the end of test the FET idea does not fly then I guess I will > stick to the SA612A. I think it was Cecil or JR who mentioned sampling > the i.f. with this circuit after the mixer stage before the i.f. filter > and all of the gain. That is the idea. > > I have been looking at NTE's line of radio IC's to see what sort of > receiver ideas one can get from their line up of chips. NTE has quite > a few IC's specifically for radio. Mixers, balanced mixers, > oscillators, i.f. agc sections, etc. > > The test output of my H101 receiver's DDS will allow me to have a LO > IN that I can change the offset of by setting of the frequency by the > receiver's software. I can then determince the exact ideal offset to > be used with any QSD idea I try and then sellect the crystal or > oscillator for that DDS frequency I used. The DDS out feature is handy. > > I have wondered if there is a way that in the future one could > control a Huff & Puff VFO via a micro controler? I can not at this > moment think of how. I did hear that some folk were looking into it > and I hope I can find that info. > > Go to <http://fairradio.com/> and look up "Nida Trainer Model 130" > #NIDA 130 for $49.50 It is a breadboard trainer with power supplies > and meters and makes a nice design center. In its catalog photo it > appears to have three breadboards. I will order one here this week. > > Dan > > > _____________________________________________________________________ > 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/
