[AMRadio] FSK mods for Valiant

Jim Candela jcandela at prodigy.net
Thu Jun 30 18:16:52 EDT 2005


   I am not a big fan of Johnson VFO's, but they are
definately a step up over Heath with the VF-1. So in
the spirit of "tongue in cheek", the easiest way to FS
a Johnson VFO is to plate modulat the rig! Actually
that comment might apply more to an Appache, then a

   On the more serious side, diode (6AL5) switching
may be fine for a fixed downward shift. You could also
add a FM reactance modulator, and key the input
voltage between two pre-determind DC levels. I once
used a W6SAI reactance modulator (6BA6) in a HEATH
VF-1. Had to regulate everything including the
filaments (on pure DC) to minimize drift, and FM from
60 hz. This worked great until the mechanical aspects
of my VF-1 degraded such that the contacts were all
shot, and frequency hopping was the result. That VF-1
was personally delivered to the landfill with a swift
kick.. I spent way too much time on the POS. :-(

Good luck with your project,
Jim Candela

--- John Lawson <jpl15 at panix.com> wrote:

>   If anyone has any direct experience with modding
> the Johnson Valiant (or 
> similar VFO) for 'real' FSK - I'd be very interested
> to hear of your 
> methods / results.
>    I have a few ideas, and BTW I intend to use a
> vacuum tube to accomplish 
> this, to maintain it's boatanchor status.  While
> there is plenty of audio 
> advice concerning Valiants, I've yet to come up with
> any concrete info on 
> wiggling the VFO with my Mod. 19.  I have a couple
> of Dovetrons to do AFSK 
> - but I'd really like to just feed the Valiant a
> sample of the local loop 
> current and make it deedle-deedle that way.
>    Cheers
> John KB6SCO
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