[Novice-Rigs] Keying of VFOs (HETERODYNED IN HOOTERVILLE)

[Ed Swynar]

Hi Brian,

Many thanks for the note & your thoughts...

Yes, I'm with you 101% on the ability of being able to monitor my
"...on-the-air" signal --- even in the A.M. mode. But I do NOT want to
strain for a weak signal through my own self-induced QRM! Hi Hi

With low voltage on the VFO, I got away with it, but with the "QRO" level
that it's at now, I'll definitely have to do something, and hopefully by
this coming Field Day weekend.

Another interesting aside: with a Hartley, the ground return for the cathode
is through about 1/3 of the tank oscillator coil...Hmmmm. I wonder what a
long shielded lead to my key / TR switch will do for stability / final
frequency...?! NO WONDER the Johnson guys used a Clapp circuit with the 122!

Will be looking forward to learning of your progress, with my thanks in
advance...

~73~ Eddy VE3CUI - VE3XZ





----- Original Message -----
From: "Brian Carling" <bcarling at cfl.rr.com>
To: "Novice Rigs" <novice-rigs at mailman.qth.net>; "homebuilttuberadios"
<homebuilttuberadios at yahoogroups.com>; "MOPA GROUP"
<MOPAGROUP at yahoogroups.com>; "FL Boatanchors"
<flboatanchors at yahoogroups.com>
Sent: Sunday, June 12, 2005 8:23 AM
Subject: Re: [Novice-Rigs] Keying of VFOs (HETERODYNED IN HOOTERVILLE)


> I can hear the free-running osc. in my rig all the time. I like it (grin!)
> What I get is a much stronger signal when the xmtr is keyed so I can
> still use it
> for a sidetone. I just got accustomed to hearing the back wave!
>
> I have some upcoming projects that include a keyed osc. using a 6GW8 for
> a MOPA xmtr.
> I will let you know how that works out, but I think with a crystal
> controlled set-up it will
> be relatively easy to tame.
>
> I will have a look at the E.R. article and see if it is something I want
> to attempt.
> I usually run the xtal osc. or VFO at around 250 - 300V on the plate and
> reduce the
> screen voltage if it's a pentode. The 6GW8 of crouse will be a  triode
> osc. running at a
> lower voltage.
>
> 73 de AF4K, Brian
>
> Copy to HomeBuiltTubeRadios for Mike Peebles & Co.
>
> Ed Swynar wrote:
>
> >Good Morning All,
> >
> >I'm curious as to everyone's success (or LACK thereof, too!) with the
keying of their homebrewed VFOs...
> >
> >I just had a piece published in ER about my HB effort along these lines,
but I discovered that changes that I made in my transmitter here recently
have necessitated more output from my outboard VFO to properly drive it.
Anyway, I upped the ante this morning by doubling the B+ going to the VFO,
but now the free-running oscillator can be readily heard (569!) on my
receiver all the time.
> >
> >I'm debating about putting a closed circuit phone jack between the
cathode & ground in the cathode follower of my 12AU7A VFO --- I could then
bring out a lead from this jack, and either place it parallel with my lead
keying the cathodes of the driver & final PA, or,  run it to my T/R switch
(just a relay, activated when I go into transmit mode) so that the lead will
be grounded ONLY when I send.
> >
> >Anyone reading this have any comments along these lines? The extra
voltage to the VFO has, indeed, improved the drive level to the HB rig, so I
definitely do want to keep the B+ at a higher level, but the "...self-QRM"
that came along with it is most assuredly NOT acceptable!
> >Any & all info re. real-world experiences appreciated, with my thanks in
advance...!
> >
> >~73~ Eddy VE3CUI - VE3XZ ("Heterodyned In Hooterville")
> >
> >
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> >
> >
> >
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