[Boatanchors] General Radio 1931-A Modulation Monitor

[bcarling at cfl.rr.com]

It seems like either USA or UK amateirs were at one time required to have an "Absorption 
Wavemeter" at their shacks to take alleged frequency readings.

I never had one either place!

Bry AF4K / G3XLQ

On 6 May 2014 at 10:02, rbethman wrote:

> Just a little information regarding Modulation Monitors.
> 
> Did you know that ALL are Northern Friends, Canadian Amateurs, were once 
> required to have on at their station to run AM?
> 
> I picked up one from the North made by Simpson.
> 
> Bob - N0DGN
> 
> On 5/5/2014 10:18 PM, Brian Harris via Boatanchors wrote:
> > I recently acquired my second General Radio 1931-A Modulation Monitor.  This one is a much later serial number (2688) than my first one (370).  On the front panel of this second is stenciled the following:
> >
> > AF33-604-16827
> > 7CAC-575975
> >
> > First question:  Can anyone shed light on the nature of this stencil?  Might the AF mean Air Force?
> >
> > Second question:  These units required a coil specific to a frequency range.  I have two coils, both of which cover .5-8 MHz in four ranges.  These are the most common coils as these units were most often used with AM Broadcast transmitters.  I would like to obtain one or two of the higher frequency coil, which I recall covers 8 - 30 MHz.  If there is an outside chance that you might have one or two of these available please let me know.  Of course I can fashion some myself but that is something I'd like to avoid.
> >
> > Thank  you,
> >   
> > Brian Harris, WA5UEK
> > cell 214-763-5977
> > email cosmophone at yahoo.com
> 
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