[BC] Listeners Loading down the Transmitter

[Bob Foxworth]

 > You can also place an 8 ohm to 1 to 10k ohm transformer across a
 > speaker (low-Z towards speaker) and use the speaker as a microphone.
 >
 > Tom Osenkowsky, CPBE


In the mid-sixties I was on my way to W. Germany to
attend Goethe-Institut and had 3 weeks to kill in Europe.
Part of my train travels took me through the DDR and
Czechoslovakia. I stayed for a couple of days in Prague.
(Today, I can't believe I even did that...)

In the hotel room was a large cabinet with a 10 or 12 inch
speaker, and a 4-position switch, labelled for the three
local radio program feeds, and an "off" position. I believe this
was nominally to keep listeners from hearing decadent
western influences, which an actual tunable radio would
provide.

Even back then I had no doubt that the "off" position
worked exactly like the intercom I had built in the 1950's
from plans in magazines that used 2 speakers, a low to
high input xfmr, and a reversing switch in the speaker
lines for talking back. I could visualize the agents
listening to me plan all sorts of currency violations etc
(or so they wished) but I did not want to oblige them.
I became a faithful listener to the Czech Second
Programme (or whatever it was) during my stay....

It was only later that I learned one reason they kept
your passport while you stayed at the hotel was so the
KGB could copy your information and look for an agent
who resembled you, so they could give him your
identity as a black agent and try to "repatriate" you..

I've never before or since seen what appeared to be a
monitoring setup that was done so ham-handedly.
But those huge dynamic speakers could pick up a lot.

I saw a studio at a college radio station back in those
days where the speaker lines were run through a patch
panel, perhaps for a similar reason. I never asked "why".
At least, they had no -60 mic lines nearby.

- Bob