dold@mitisft.Convergent.COM (Clarence Dold) (01/12/91)
in article <37881@cup.portal.com>, thad@cup.portal.com (Thad P Floryan) says: > "rumored" to have occured either at Ft. Bliss TX (Air Defense School) or at > White Sands Missile Range circa late '50s or early '60s: a soldier took a > shortcut through the "beam" in a multi-megawatt RADAR installation and keeled > over, and it wasn't apparent what happened until after the autopsy: certain > internal organs were cooked. This incident is "rumored" to have been the I worked on Heavy ground Radar in the Air Force, with pulses transmitted at ~ 5 MegaWatts. While on the roof of one of the buildings, I heard a bzzt-bzzt-bzzt that would repeat occasionally. After a minute or two, I realized it was the cyclone fence rattling from the radar emissions of a radar set about 75 feet away. We were supposed to be in a 'blanked' area of the radar set, but obviously we weren't. I have no known side effects from this exposure ( although I am losing my hair now, 20 years later ). When the radar was dismantled in 1976, we found flies inside the waveguide. They were dead, but I imagine they starved. They didn't look burned, even after 20 years of fairly constant high level radar exposure. Hmm, a 20 year old fly carcass? Never thought about that before. -- --- Clarence A Dold - dold@tsmiti.Convergent.COM (408) 435-5293 ...pyramid!ctnews!tsmiti!dold FAX (408) 435-3105 P.O.Box 6685, San Jose, CA 95150-6685 MS#10-007
thad@cup.portal.com (Thad P Floryan) (01/12/91)
dold@mitisft.Convergent.COM (Clarence Dold) in <1761@mitisft.Convergent.COM>
writes:
[...]
When the radar was dismantled in 1976, we found flies inside the
waveguide. They were dead, but I imagine they starved. They didn't
look burned, even after 20 years of fairly constant high level radar
exposure.
[...]
Flies are smaller than 1/4 or 1/2 wavelength at "most" the frequencies at
which high power RADAR operates, so would not have been "cooked" resonantly.
If you think back of that chain-link fence which "sang" when hit by RADAR,
think of the length of each side of each "square" formed by the wire and you
can deduce the frequency (or harmonic thereof) at which the RADAR operated.
My reference to human eyeballs and testicles was based on an approx. 1GHz
frequency whose wavelenth "likes" objects that size.
Reason I bring up the above points is that once I had a "problem" with a
computer I designed in that one trace on the motherboard tended to resonate
and caused all sorts of weird problems that didn't occur on the prototype
which I hand-made; the guy who did the PC layout for Teflon-fiberglass simply
wasn't familiar with high-frequency considerations for layout. Computers
using ECL or GaAs components are also susceptible to poor layout at the higher
frequencies.
I'll have to show-'n'-tell (via photos) some of my previous designs at even
higher freqs; the cases, traces, connectors, etc were all gold with ceramic,
sapphire or even diamond substrates, and, except for the occasional chip
capacitor, one wouldn't recognize ANY component on the microstrip "boards".
Designing with clocks far in excess of 1GHz often required empirical "tricks"
that mimic black magic and voodoo! And the completed circuitry was nicknamed
"Tenement Housing" (picture that in your mind).
When people "boast" of 50 MHz-clocked computers today, I still think of that
as practically DC. My lab operated with frequencies from "DC to daylight",
and the designator "THz" wasn't that uncommon.
And a short anecdote in closing: back when I was doing all this stuff, the
term "GHz" didn't even exist, we used "GC" or "GCPS" (Giga Cycles [Per Second])
.
When the standards committee wanted to honor Hertz with "Hz", we all protested
with a petition claiming they should instead honor Charles Proteus Steinmetz
and we'd then be able to continue using "CPS"! :-)
Thad Floryan [ thad@cup.portal.com ]