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Richard Knoppow · January 27th 09, 02:07 AM posted to rec.radio.amateur.boatanchors

"David G. Nagel" wrote in
message ...
Jon Teske wrote:

On 25 Jan 2009 12:50:41 -0500, (Scott
Dorsey) wrote:

George McLeod wrote:
Would anyone have a circuit, or know where to find one,
for the Conelrad
device as marketed by Motorola and Heathkit.
What is this device? Does it automatically tune the
radio to a CONELRAD
frequency?
--scott

I lived in this era. Back in the 1950's there was a
program called
CONtrol of ELectromagnetic RADiation. Subtitled CONELRAD.
All AM
radios (FM was in its commercial infancy, we only had
Public Stations
in the FM band) had little triangles with the Civil
Defense logo at
640 Kcs and 1240 Kcs. [Kilocycles (per second) here is
not accidental,
Hertz, as a term to mean cycles per second, was not
adopted until the
mid-1960's.] In the event of an emergency, usually
interpreted to be
an attack upon us by the Russians (this WAS the McCarthy
era after
all) you were supposed to tune your AM radio to one of
those two
frequencies for information on what to do. Inplicit in
that was that
all other radiostations would get off the air so that
they could not
be used as homing devices for attacking aircraft. The
fact that there
were other methods to navigate was blithely ignored.

About 1957, CONELRAD was expanded to include amateur
radio stations
and all stations were obliged by the FCC to have a
CONELRAD monitor
which would tell you that an emergency was declared, that
you were to
get your own station off the air, and like the rest of
the population
tune to 640 or 1240 AM.

This ruling was more observed in the breach than the
observance. And
few amateur stations did anything about it. [My
response...I was a
teenager then...was to look for a mushroom cloud. If I
saw one, I'd
get off the air. :-)

A few companies built add-on CONELRAD monitors. If I
remember
correctly, you attached the device to an ordinary AM
radio which was
already and always tuned to 640 or 1240 Kcs. (1240Kcs.
actually
happened to be the frequency for the station in my own
hometown in
Wisconsin.) When some keying signal came on, the
CONELRAD monitor
would alarm and then you were to get off the air. It
didn't retune any
radio to anything, it just told an alert went off as
broadcast on one
of those two frequencies...at least that was all a ham
version did.
In theory, you could just have a small radio playing in
the background
which supposedly would tell you the same thing.

In actual tests, which were conducted from time to time,
just as
Emergency Service Tests are occasionally heard now. All
of a regions
stations got on one of those two frequencies (to confound
the enemy's
direction finders) and they had some sort of switching so
that they
all broadcast the same message from "Big Brother" but
broadcast them
in some sort of rotation. The few tests that I actually
heard knocked
our local station off the air, but the "emergency"
broadcast itself
was total gibberish because there were too few stations
in our rural
part of Wisconsin by day, and nighttime propagation was
too screwy to
provide any responsible path.

I don't remember when CONELRAD died as I went off to
college in 1960
and wasn't on the air very much and not at all when I was
in school.
It was dead when I got back on the air with any
regularity after I had
graduated..

Heathkit did indeed built such a monitoring kit. It was
in the same
size box as their famous QF-1 Q mulitiplier or their
earliest SWR
in-line monitor, one of the first with a Monimatch
architecture. It
cost somewhere between $10 and $20 as a kit IIRC, but
that was too
much allowance money for me to spend. Even as a teen, I
had a keen
sense for Governmental BS (which paid off well later as I
was a career
Federal Employee for 35 years in the intelligence world.
You needed a
steep skirted BS filter to work in that environment.)

CONELRAD was one of the biggest governmental flops ever
in the
communications arena.

Jon W3JT (K9CAH back then.)

Jon;

An excellent summation of CONELRAD. The only correction is
the lower frequency. It was 620 Kcs which is half the
upper frequency of 1240. This was for reception at the
higher freq by use of the harmonic effect.

When I was in high school in the late 50's we had a school
fm broadcast station. Our CONELRAD detector was a standard
receiver with an addon device that squawked when the
carrier was lost. Our control station was Radio station
WOWO in Fort Wayne IN. We tested the receiver every hour
by pressing a phone jack in. This acted like the loss of
carrier from WOWO and sounded a LOUD horn. When WOWO would
loose it's carrier due to what ever it really got your
heart going. We were in the middle of the great nuk war
threat and never knew if or when the balloon would go up.
HI HI..

CONELRAD operated by switching the active carrier of
several radio stations around the country in a random
sequence so that Soviet bombers could not use radio
navigation to locate any specific target for bombing.

I agree that CONELRAD and the whole CD effort, for that
matter, was a total flop. Great PR but a flop never the
less. Growing up just south of Cleveland OH and the later
near Grissom AFB (a SAC base about 60 miles north of
Indianapolis IN I held no expectations of surviving any
nuk attack.

Dave Nagel
WD9BDZ

I'm afraid that 640khz _is_ the correct lower frequency.
Somewhere, buried in some archive, the developmental
documents for Conelrad may still exist and may explain the
choice of frequencies. I think mostly it was to have a
frequency that would be usable for any BC station. I also
don't remember (if I ever knew) the power stations were
supposed to use, I think quite low, perhaps a couple of
hundred watts.

--

--
Richard Knoppow
Los Angeles
WB6KBL