"Hoges in WA" wrote in
:
BTW - can you please repost that story about the fake radar you aimed
at the Russian fleet? I can't google it up and I've told a Pommy mate
of mine (ex-submarine-carried Russian linguist) a bit about it but I
don't know enough electronic stuff to tell him properly
thanks
Sure. It was great fun playing with RF.
The forward radar mount on our ship had an air search radar on it,
AN/SPS-6 from Korean War era. We really didn't have a use for it as we
had no way of defending ourselves being a floating shipyard, a service
ship, so it was decommissioned but I got them to leave the mount and its
electronics working because I wanted to use it for a big TV antenna for
the Crew's TV antenna system I was installing.
We put two big long Winegard VHF-UHF broadband log periodic TV antennas
up there that were anodized blue. They each had two VHF log periodic
sections that pointed inward to a long UHF log periodic that stuck out
the front towards the station. We stacked two of them on top of the
radar mount about 80' off the water on top of the forward king post. To
keep the cable from winding up around them as the ship turned and the
gyro input kept our antennas pointed to the same compass point, the
reason I wanted to keep the original radar mount active, we built some
slip rings to run the RF through into the base of it. You could leave
them rotating like a real radar, which is what we did for this story.
We weren't any kind of high tech ship, being a destroyer tender. Hell,
our HF transmitters were from WW2! But, for some reason, on the Med
Cruise (my first), this Russian ship kept shadowing us for the longest
time and they were taking pictures of our old 1952 ship! It caused quite
a stir during the Cold War as it was right after the Israelis tried to
sink the USS Liberty (
www.ussliberty.org). We traveled alone, too!
I finally noticed, one day, the Russians were intensely interested in our
new "secret weapon" antenna located on the forward king post! THEY WERE
TAKING PICTURES OF MY TV ANTENNA STACK! I pointed this out to my Comm
officer and Captain showing them the long lenses pointed towards the TV
antenna, and asked my captain if I could play some games with them using
the antenna. He loved this idea.
I worked in the Metrology Lab, the electronic calibration lab, on the
main deck, aft. One of the things we did was calibrate peak responding
RF power meters used to measure radar peak power output (after it was
attenuated by a calibrated coupler, not in megawatts). To cal these
meters I had a "power pulser" that had wide bandwidth from 1GHZ to 12 or
14 GHZ in several bands. It's output was about 1KW PEAK power with
variable pulse width, repetition rate, etc. you could vary all over the
place to test the meter's response you were calibrating.
So, I took the power pulser and a section of large coax with several
different frequency bands of waveguide adapters and feed horns (feed
horns couple the RF out of waveguide into the open air, in both
directions, to match the impedance of the air to the impedance of the
waveguide. They will radiate at CONSIDERABLY higher effective radiated
power than their input because they are very directional.
I borrowed a box of powered carbon from the electricians that would
absorb the RF energy when I pointed the feed horn into the carbon,
turning RF into heat. I took all this to a light lock deck hatch we used
to keep from radiating light at sea from the lights inside the ship.
This little compartment was flat black with a plastic black curtain
hanging over the opening so they couldn't see me and my contraptions.
We set the "secret weapon" antenna to slow rotation. I could see where
it was pointing with a mirror attached to the handrail near my hatch.
Every time the antenna pointed towards the Russians, I took the feedhorn
out of the carbon box and pointed it at them on "some frequency, rep
rate, pulse width, etc.", then put it back in the box. While it was in
the box, I changed frequencies, rep rates, pulse widths, everything, even
feedhorns as I had about 10 seconds between "sweeps". Some sweeps I just
cut it off to "listen mode".
God, every ECM antenna that rotated spun around and pointed at us on that
ship! I kept this up for hours, on and off. Whenever we'd start it
rotating, I'd start radiating towards their ship, from either side of
ours. They'd get closer to receive every pulse.
Then, we simply hand slewed the antenna forward and stopped......our
mission complete.
The Russians stayed about 8 more hours and went away to "analyze" their
findings. I never heard anything about it beyond that point. It was
great fun for a bored crew to play with. I wonder how many satellite
photos of USS Everglades (AD-24) were taken with closeups of our TV
antenna carefully poured over in KGB or military intellegence HQ?...(c;
BTW, the antenna could pick up Charleston's VHF TV stations over 130
miles at sea, distributed to every shop throughout the ship. As "Cable
Operator", I had quite a lot of political power and could get most
anything I wanted from anyone aboard. My captain, especially, couldn't
believe how great his TV looked from 100 miles offshore all up and down
the coast. I'd go up about once a day and "correct" the small angle
change our breakneck 17 knots cruising speed caused if we were heading up
the coast at the hand controls of the radar mount in CIC. But, with gyro
azimuth correction, if the ship took a turn for some reason, the antennas
stayed pointed at the TV stations very nicely.....
The Russians loved it.....(c;