[GreenKeys] Brecom

[Sheldon Daitch]

Interesting on the tie-in with VOA, Victor, and for the weirdest
of coincidences, I happened to be moving some old papers
around in the home office, and a file folder fell open with
a copy of an April, 1970 article from the old BM/E magazine,
"Multiplexing Teletype Signals at an AM Station," written by
Larry Peden and John W. McMains.  I saw the folder BEFORE
I read this thread on Greenkeys!

Peden is credited as secretary-treasurer and McMains was a
project engineer with Barry Research Corp.  BR was calling it
the PM*PM system.  Two components made up the
transmit side, the BR TCT-2 teleprinter convertor was the
interface between the TTY data line and the transmitter.
In the transmitter was the second BR component, the TPM-2,
phase modulator.

Two quotes from the article:

"The PM*PM system has been successfully tested by the Voice of
America using their regular shortwave transmitters to send hard
copy overseas.  The system has not been used in domestic AM
broadcasting and FCC approval has not yet been ought."

"To provide further immunity from noise and signal fading, diversity
reception is employed with two receivers and an automatic
AGC-controlled selector.  This technique was used in the VOA
tests.  It might be unnecessary if only the stable ground wave
from a medium-frequency broadcast station were used."

I recall folks at Greenville VOA telling me about it, but to the best of my
knowledge, by 1979, any operation of this nature had been abandoned.
I also don't ever remember seeing any of the BR equipment out at the
two TX sites in Greenville, but then again, I could have missed them.

73
Sheldon
WA4MZZ



Victor Blackwell wrote:

> It seemed like maybe 1962, about a year before Kennedy was assassinated and
> maybe a few months before Drake introduced the TR-3 at the Dayton Hamfest
> when It was still at the hotel in downtown Dayton.  I did not get all the
> details until I interviewed for a job with the USIA many year later.  One of
> the persons interviewing me kept repeating my name out loud like he was
> trying to remember something.  Then on one interview he told me he had an
> interesting story to tell me.  Then he told all.  He he.  I did not even
> know any government employee would have even known my name.  The interview
> occurred about the same time the VOA was considering taking the Bethany
> relay station off line.  They were going to replace the relay with
> satellites.  I told them that the satellite relays would be easier to jam
> than the high power transmitters at Bethany.  They kept Bethany on for a
> good number of years after this.  The people who worked there wanted to save
> the place.   It's a small world.  I am glad to hear about this from other
> parts of the system.
>
> Rockwell was the CE for WLW at the time and Dick Walker of VOA interviewed
> me.  They have both since passed.
>
> Vic  AD8K  ex W8VST  On rtty in 1957
>
> Bob Drake owned a model 26 but never used it.  It just sat under a bench in
> the lab.  And I discovered the RTTY on LW when I was giving a Collins 51-j4
> the old drop test for stability.  I heard the warble on the carrier before
> the receiver slipped out my hands.  The beat note of other BC stations was
> clear as a bell, rock solid.  I would love to live those days over again.
>
> Vic
>
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