[GreenKeys] FRF FSK conv. (was - Two eBay Novelties)

[Duncan Brown]

The FRF looks like an early version of the CV-31B/FRA-7 used in the 
AN/GRC-26 (c1950) and discussed here recently.

I wonder about the "Warning - Radiation exceeds safe limit -Do not use 
aboard ship" label.  Were they worried about RFI?  to or from the FRF??

The specification for the FRF is available at 
http://jptronics.org/radios/Military/JANAP161/an.fcfg/an.fga-type.frf.pdf .  
It mentions tone _oscillators_ at 170 cps apart.  It almost implies a 
multiplexed system of 170cps shift signals on one carrier or sideband 
(which was done in WWII), but I think the FRF (and certainly the CV-31) 
is a single channel output (one TTY signal). It was probably designed 
for 850 cps shift, though might work down to 425 cps shift.  Military 
converters often had a keyed tone (OOK) output if the demodulated TTY 
signal needed to be sent any distance from the RX site to where the 
actual TTYs were located.

The AWA Museum has a CV-31B/FRA-7, so we will not be bidding on this, 
but it does belong in a museum!

have fun,

Duncan
K2OEQ

On 08-Feb-14 21:04, David Burns wrote:
> WWII Navy Western Electric Model FRF Receiver Frequency Shift Ham For 
> Teletype 
> <http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221370706399&fromMakeTrack=true>
> This is an odd duck...Navy dual-channel I.F. demodulator with 170 
> shift, but preset at eight odd military frequencies, designed to 
> interface with 1940 RBB/RBC battleship receivers.  There is stuff on 
> the web if you search with the "CW-####" FRF numbers.  "Not for 
> shipboard use", but the shipboard equivalent equipment seems to have 
> been canceled.  Which would explain why this unit was never used.  I 
> sent mail to the seller suggesting they list the associated teletype 
> machine /they still have crated up!/ (That could be very interesting!)
>
> Telegraph / Teletype Machine WUTEL Western Union Quotation Service 
> <http://www.ebay.com/itm/231153851639?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT>
> This ticker is missing the motor (and other parts?)
>
> -Dave in Boston
>
>
>
>
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