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

[Nick England]

I have manuals for similar equipment and I'm pretty sure the tone
oscillators are indeed for the output tone for transmission of the
demodulated TTY signal to remote equipment.

RFI from the FRF or any piece of receiving equipment was a big concern
shipboard in WW2 - whether it really mattered or not is a recurring topic
of discussion here...
 Nick England K4NYW
www.navy-radio.com


On Sun, Feb 9, 2014 at 4:22 PM, Duncan Brown <duncanancy at earthlink.net>wrote:

> 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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