[GreenKeys] McElroy keyer - Wheatstone tape?

[Jack]

Sounds a lot like the way the Model 14 TD's could be modified to send
CW. They
used a polar relay as the "storage device".

Jack K0TTY

NNNN



-----Original Message-----
From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Nick England
Sent: Sunday, February 26, 2012 11:39 AM
To: Greenkeys
Cc: Tom French
Subject: [GreenKeys] McElroy keyer - Wheatstone tape?

Thanks to Tom Tillson's manual, I got my newly-acquired ex-USN
Wheatstone perf making all the right holes in paper tape (after
building it a 110vdc supply).

So I hauled the McElroy XTR keyer (10wpm to 200 wpm ) off the shelf
and started cleaning it up.
http://www.navy-radio.com/xmtrs/control/keyer-mcelroy-91.jpg
http://www.navy-radio.com/xmtrs/control/mc-67.JPG

Looks like it works OK, but not the way I expected:
I figured there would be some mechanical latch mechanism for the
hole-reading contacts that would close to form each dit and dah.
But no, it appears this device has separate start and stop contacts,
and depends on some external device to actually turn those signals
into each dot and dash to key the transmitter.
i.e. for a dit, the start contact closes briefly , then a little later
the stop contact closes briefly
- for a dah, there is a longer pause between the start and stop
closures.

So, does anyone have any clues as to what the required external
"flip-flop relay" would look like?
I mean, I can certainly build something using IC's or tubes, but what
was really used to run at 200wpm back in the day  (1941 according to
the date on this keyer).
cheers,
Nick K4NYW
www.navy-radio.com
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