[GreenKeys] Info needed on CV-278/GR

[Duncan Brown]

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 <Duncanancy at earthlink.net>
> Date: 11/5/22 4:42 AM (GMT-07:00)
> To: Mike <mmcauley at cox.net>, GreenKeys at mailman.qth.net
> 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 <mmcauley at cox.net>
> Date: 11/5/22 01:39 (GMT-05:00)
> To: GreenKeys at mailman.qth.net
> 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
>
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