Mike,

Rattrig.com has the -20 & -35 CV-278 manuals.

Nothing special to receive 425 Hz shift, just tune it in.  I don't remember what the FSK detector bandwidth is or what kind of shape it had, but I have copied the German weather station DDK on a CV-278.  The schematic shows four tuned circuits in the demodulator, so probably pretty wide & linear (for drifting transmitters).

Note that the AN/GRC-46 series ran a 20 ma loop.  I don't know how long the keying relay would last at 60ma. Might be alright at 60, but best to run it in a 20 ma loop, as designed.

Have fun,

Duncan
K2OEQ


On 05-Nov-22 10:52, Mike wrote:
Thanks Duncan,  I did look at the rattrig manuals but didn't see anything specific for the CV-278. 

But knowing that it's 850 shift is helpful, and I do have the R-392 to connect to.  How is the switch made to convert to 425? 



Mike


-------- Original message --------
From: Duncanancy <[email protected]>
Date: 11/5/22 4:42 AM (GMT-07:00)
To: Mike <[email protected]>, [email protected]
Subject: RE: [GreenKeys] Info needed on CV-278/GR

Mike,  

It was designed for 850 hz shift and will do 425 hz shift, but don't know about 170 hz.

Takes 455khz IF from R-392 receiver 

Have fun

Duncan 
K2OEQ 




Sent from my Kleinschmidt TT-4/TG, the US Army's first portable digital communications device, 1950-1980




-------- Original message --------
From: Mike <[email protected]>
Date: 11/5/22 01:39 (GMT-05:00)
To: [email protected]
Subject: [GreenKeys] Info needed on CV-278/GR

Hello group,

Recently acquired a CV-278/GR "CONVERTER, FREQUENCY SHIFT"

All I can find online is a TM maintenance manual which is somewhat limited.

I'm looking for what the specifications and capabilities are for this unit. (Freq, shift, etc)

Anyone familiar with it?

Thanks...


Mike
KD7VRG
Tucson, AZ