[Boatanchors] [Milsurplus] General Radio 1931-A Modulation Monitor

[Sheldon Daitch]

Brian,

You mentioned the two sets of coils, and that forced me to take a look at my manual for the 1931-A, and sure enough, two sets of coils were indeed made for this unit.  I never knew that.

My manual states the HF range is 3 to 60 MHz.  

Let me ask you about something in the manual.  Section 5.2, the manual has full scale for the Carrier Meter as 400 microamperes, but a previous owner of the manual has inked in 800 microamperes for full scale.  What does your manual and maybe your meter indicates is full scale?

73
Sheldon

-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Brian Harris via Milsurplus
Sent: Tuesday, May 06, 2014 5:19 AM
To: Boat Anchors; Military Surplus
Subject: [Milsurplus] General Radio 1931-A Modulation Monitor

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