Small world... I had 1/2 time job while undergrad physics senior. I used a
multi channel chart recorder to print out the audio signatures of H bomb
blasts from 4000 nautical miles away via undersea propagation. That is
except on Monday mornings and Friday afternoons when the "Fleet" sailed out
of and then back into San Diego with their powerful radars transmitting. My
recorder strip chart showed their primary and secondary lobes. A few yards
away in a screen room much more delicate work progressed without
interference.
I think freezer wrap would do a good job as shielding against RF
interference.
Patrick AF5CK
-----Original Message-----
From: Bill Ogden
Sent: Tuesday, October 01, 2013 11:55 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Shielding - slight OT
A quick real story -- Long ago and far away (Southeast Asia) we installed
a small computer system. It had a problem. At fairly regular intervals
(about every 15-20 seconds, IIRC) it would often take a "red light" error.
A bunch of people worked on it; various components were replaced, etc,
etc. Nothing helped. One day a team member was looking out a window and
happened to notice that a radar antenna seemed to have the same period of
revolution. A quick check verified the problem. A roll of common aluminum
foil (from the PX), hung in overlapping strips, temporarily solved the
problem. The machine was later moved to a different location. I cannot
remember the exact details of the foil placement.
The goal of shielding a ham shack is not quite the same thing, but a
simple foil "wall" did work in at least one instance.
Bill
W2WO
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