[Boatanchors] W2EWL VFO range? New Question

[Gary Schafer]

I never played with the pacemaker but with the 10B, 20A I found the best way
to adjust side band suppression was not to use a tone and tune for minimum
ripple on a scope as they suggest, but listen on the opposite side band with
a receiver and talk into the mike or do an "oooh" sound. This is much easier
to get equal suppression on each side band.

I also found that the coupling between the 9 MHz coils for the balanced
modulators was critical to getting the proper phase shift. Tuning alone will
not do it. Increasing or decreasing the coupling is also needed. That is
done by moving one coil in its slot in the chassis.

73
Gary  K4FMX

> -----Original Message-----
> From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-
> bounces at mailman.qth.net] On Behalf Of David C. Hallam
> Sent: Tuesday, March 22, 2011 1:17 PM
> To: boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] W2EWL VFO range? New Question
> 
> Sine the topic is phasing SSB rigs, I am going to ask for ideas with a
> Johnson Pacemaker I am refurbishing. Johnson went a different route in
> the Pacemaker. The SSB signal was generated at a different frequency on
> each band and then mixed with Johnson's standard vfo, 3-3.5 MHz.
> 
> My problem lies in the RF phasing circuit. On some bands, particularly
> 40 & 20, I am getting harmonic output from the crystal oscillator. On 40
> the oscillator is 4 MHz and 20 is 11 MHz. Each of the 5 crystal
> oscillators has its own tuned circuit, slug tuned coil and capacitor.
> Johnson says to tune each oscillator to maximum output OR 1.5V RF
> whichever is less.
> 
> With the harmonic content of the oscillator, I can not get the required
> 90 degree phase shift. for the balanced modulator. The coils and
> capacitors are a bear to get to and I have not measured the inductance
> or capacitance of the components. I have tried different crystals.
> 
> Ideas?
> 
> David
> KW4DH
> 
> On 3/22/2011 12:31 PM, Robert Nickels wrote:
> > On 3/22/2011 10:48 AM, D C *Mac* Macdonald wrote:
> >> Single conversion could theortically cover 3.7-5.0 with a subtraction
> >> mixing scheme and 13.0 - 14.3 by using an addition mixing simply
> >> by tuning the final (IIRC).
> >>
> > These basic phasing rigs are a great learning experience and I have to
> > admire you guys who tackled such a project back in the Eisenhower era!
> >
> > 73, Bob W9RAN
> > ______________________________________________________________
> > Boatanchors mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Boatanchors at mailman.qth.net
> >
> > List Administrator: Duane Fischer, W8DBF
> > ** For Assistance: dfischer at usol.com **
> >
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> 
> --
> "I bring reason to your ears, and, in language as plain as ABC, hold up
> truth to your eyes." Thomas Paine, December 23, 1776
> 
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
> 
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
> 
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html