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Title: VFO voltage for CE 20A ?? Post by: wa2tak on December 12, 2022, 11:23:30 AM I've read the 20A would "like" a 9 v pk-pk from a vfo.
I've read that the Lakeshore Bandhopper works with the 20A. The Bandhopper manual state output " 3 - 8 volts ". I'd like to use my military URM 25F signal generator until I get a 'real' VFO...if necessary. The unit puts out 3 v pk-pk. What say folks? Title: Re: VFO voltage for CE 20A ?? Post by: wa2tak on December 12, 2022, 01:20:07 PM First...I truly hope that my questions do not disturb anyone.
ALL 'things' with the 20A are new to me...with what little info I can find...esp the "manual"...leaves me little choice on where to get help...thank you for your patience!! Like finding out that a vfo is REQUIRED for AM!!! I find getting Central Electronics gear IS history making!...may the Great Spirit take good care of Mr. Schaum. Have a good 12 watts CW..7.040..and that magic eye works fine tuning up...can hear it in my receiver. I hooked up my 3 v pk-pk sig gen to the xtal socket. Went to AM...VFO...sweeped a LOT of frequencies...and esp. expect something at 7.040. Nada....no carrier...any place Sooooooooooooo...don't know if my "vfo" is not putting out enough juice...or...have an AM issue. Title: Re: VFO voltage for CE 20A ?? Post by: KC2ZFA on December 12, 2022, 01:29:12 PM https://www.frostburg.edu/personal/latta/ee/vfo/vfo.html
and scroll down to the voltage step up transformer. Title: Re: VFO voltage for CE 20A ?? Post by: wa2tak on December 12, 2022, 01:39:45 PM Will that 1:2 voltage step up...3v:6v...be sufficient for a 20A????
Looking for 'clarification' on the subject. It appears that different bands need different VFO voltages??? Title: Re: VFO voltage for CE 20A ?? Post by: wa2tak on December 12, 2022, 01:58:02 PM Looked more closely...amp + xmfr should do...
Title: Re: VFO voltage for CE 20A ?? Post by: Carl WA1KPD on December 12, 2022, 02:46:39 PM Remember the VFO or crystal "frequency" needed with the 20 is not the actual frequency you want to transmit on. And the offset is most likely different than what is specified. I have dealt with two of them and the heterodyne crystal on both had drifted in frequency.
Good luck Title: Re: VFO voltage for CE 20A ?? Post by: wa2tak on December 12, 2022, 03:25:14 PM I've been 'hearing' quite a bit about 'drift'...
Probably not an issue on AM....but certainly SSB. Guess I'll have to deal with that some goodly way down the band... Title: Re: VFO voltage for CE 20A ?? Post by: KC2ZFA on December 12, 2022, 07:42:47 PM you need to wind your toroid for a 1 to 3 voltage step up (1 to 9 impedance).
Title: Re: VFO voltage for CE 20A ?? Post by: wa2tak on December 13, 2022, 09:19:18 AM I've read about them only...NO experience / hands on. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Would you please give me the details? Rather than take up 'space' on the forum...you can email me at: info@tak-tenna.com Tnx, Steve |