[GreenKeys] Keyer KY-463A?

Sun Feb 16 19:55:41 EST 2020

It looks like the loop supply for the M28, that could be keyed by on-off 
tone keying.  It kinda looks familiar, and Nick has identified it.

Long ago & far away, in an ASA facility, we had racks consisting of a 
R-390, AN/FRA-86, & M28 RO. Hung off the side of the rack was a little 
box that had a "KY-xxx" nomenclature. There was a large (6 ft rack) 
audio tape deck nearby. I had assumed that the FRA-86 had a loop supply 
and drove the M28 directly, and the keyer box generated the on-off tone 
that was sent to the tape deck. The keyer would also have to detect 
on-off tones from the tape deck to drive the M28.

Since the FRA-86 was designed for intercept/monitoring, it makes sense 
that it would not have a loop supply, but only put out the on-off  
tones, which could be recorded directly on audio tape. Thus the KY-463  
is  a "re-keyer" and converts from on-off audio tones to on-off DC 
current and vise versa.

The other thing interesting that I remember about the KY-463 was that it 
had a "FOUO" (For Official Use Only) label on it. The manual said 
something to the effect of "This equipment is not classified, but may be 
used with classified equipment, so care should be used when discussing it."

Thanks, Nick!

Duncan, K2OEQ
USASA 31J20; 33B20; 33F30

On 2/16/2020 18:14, Nick England wrote:
> I found operation and troubleshooting AV materials for the KY-463/FGC 
> "rekeyer" listed in a catalog of AV materials for  US Army Intercept 
> Equipment Repairmen (MOS 33S). As you might expect, other materials 
> listed in the same catalog are for radio intercept station equipment 
> (receivers, recorders, antenna systems, AN/FRA-86 DFSK converters, etc.).
>
> And I found this in a 1966 USMC R&D report -
> " IMPROVED TTY KEYER Based on size, weight and primary power 
> considerations, the AFSAV 39C Rekeyer used in the Green Elephant R & D 
> systems will be replaced with the KY-463A/FGC Keyer Design of a 
> combination mounting shelf and front panel, capable of rack-mounting 
> four KY-463A/FGC Keyers, has been completed. The mounting panel 
> requires the same rack space formerly occupied by one AFSAV 39C 
> Rekeyer The following controls and indicators from each keyer have 
> been brought out to the front panel: POWER ON-OFF Switch POWER ON 
> Pilot Light POLARITY Switch Phone Jack Mounting panels are now being 
> fabricated for installation in the Green Elephant R & D systems, 
> although the keyers are not expected to be available until the second 
> quarter of fiscal year 1967 installation of the keyers and panels in 
> the systems can easily be accomplished in the field, if necessary"
> "Green Elephant" seems to refer to truck mounted radio intercept 
> stations such as the USMC AN/TSQ-88
>
> And the AFSAV 39C rekeyer is:
> "The CV-1627/URR (AFSAV 39-C) two-channel rekeyer is used to convert 
> Keyed Tone (KT) signals received from the AN/FRA-86, or similar 
> terminal equipment into d.c. pulses to operate teleprinters for one or 
> two independent single-channel teletype systems. The input is Keyed 
> Tone with a
> minimum element length of 5 MS.,"
>
> So adding all this together, makes me guess that the KY-463A/FGC was 
> used to convert keyed tones to TTY loop signals. The keyed tones 
> presumably came from someone listening to the other guy's RTTY 
> transmissions.
>
> Just taking a wild wild guess, do they look anything like these 
> Telesignal modules?
> http://www.navy-radio.com/rtty/fgc60/telesignal-1706-01.jpg
>
> Nick England K4NYW
> www.navy-radio.com <http://www.navy-radio.com>
>
>
> On Sun, Feb 16, 2020 at 12:54 AM Robert Goff <robert.h.goff at gmail.com 
> <mailto:robert.h.goff at gmail.com>> wrote:
> >
> > I ended up with three of these keyers in a box of random M28 parts -
> > all of them marked DoD.  Looks like they fit into the M28 LESU.
> >
> > Not much information online - anybody know what these were used for?
> >
> > Thanks and 73,
> > de Robert W7MKA
> >
>
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