Re: [AMRadio] FSK mods for Valiant

[Byron Lichtenwalner]

John
I has been a while since I used a loop and keyed a tube trqnsmitter, but
here is whaqt I remember.
VFO keyers in typical CW/AM rigs are single band devices since the shift
multiplies as the VFO output multiples to the next up band.
Since the keyer is adding (or subtracting) capacitnce to the VFO circuit ,
any change if VFO frequency will also change the shift frequency.

I am not a fan of AFSK.  But if you can generate a carrier with the SSB
adapter, think about keying the BFO  in that section.  Then a single keyer
will give you shift over the entire range, and side band selection will give
you the choice of mark/space signalling.

Byron, W3WKR

Re: [AMRadio] FSK mods for Valiant

[Jim Candela]

John,

   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
Valiant.

   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,
Regards,
Jim Candela
WD5JKO

--- John Lawson <[EMAIL PROTECTED]> 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
>
__
> AMRadio mailing list
> Home:
> http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio@mailman.qth.net
>