Yes...the last "real" job I had was for a telecommunications services provider. They installed and maintained towers, as well as the cellular, and microwave equipment, associated with all of it.
The guys used to do that to prove that the ovens weren't really all that well insulated, but I always wondered if there was another reason that might happen. A
Been there..done that..still remember the spasms.. but I wasn't stupid enough to use my tounge.
Fingers were quite enough.
Gunner
"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown
The shielding is not required to be perfect, cutting the ~600 watts RF internal leftover-heating power to something like a milliwatt of leakage per centimeter of door seal (I don't recall the exact number, but it will be *somewhere* on the FCC website), which would be something like
100 milliwatts total leakage for a small door. The intent is only to reduce the leakage to safe power levels; there will always be some leakage.Also, the seals on a microwave oven are only required to work at 2,450 MHz, while cellphones are more like 900 MHz, and some very good kinds of door seals (choke seals) are tuned to a specific frequency, and so would fail miserably at 1/3 the design frequency.
So, if you are close to a cellphone base station, one can imagine that the phone inside the microwave could still hear the call and ring.
Joe Gwinn
Because, as we all know, some parts of automotive carburetors run on magic. And like the smoke sealed up inside working electronic components, you really don't want to let it escape. :)
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Depends on the Poodle.
Larry Jaques wrote in news: snipped-for-privacy@4ax.com:
Acually, I was much more attracted to Jane Hathaway. I later found out that Nancy Kulp was gay. It never fails...
Thinking about that, the front has a pierced panel that blocks radiation at around 2.5 gigahertz, however the cell phone runs at around 800 MHz so it's possible enough of that frequency will leak through to make it work.
N
A CRT that's not connected to the HV lead won't have any path to ground to bleed the charge off, it'll pick up static from the air over time.
Cool - thanks for the explanation!
A
I suspected so. I imagine that if you peed from a height of more than a few feet, the stream of urine would break up into droplets and would not form the necessary conductive path. Still, I wouldn't want to try it with 25 kV.
Chris
Tom Miller wrote: >
I suspected so. I imagine that if you peed from a height of more than a few feet, the stream of urine would break up into droplets and would not form the necessary conductive path. Still, I wouldn't want to try it with 25 kV.
Chris
Yeah on that chance that a solid stream did connect, pee is a pretty good conductor of electricity, I know people who've accidently peed on electric fences and I do know for a fact that it'll bite you.
On Sat, 25 Jun 2005 22:55:44 GMT, the opaque "H.C. Minh" spake:
Huh, HORSEFACE? I'd rather have Granny after me.
It doesn't surprise me.
----- = Dain Bramaged...but having lots of fun! =
In New Zealand they have interisland undersea lines which run at 500 KV DC IIRC and they wash the salt off the insulators with a 'chopped' spray jet of water. Scary job IMO.
N
Thanks for the reply.
I had heard that it meant "frog in forest", or words to that effect. The "forest" part makes sense, but maybe not the "frog" part.
Duck trapping wouldn't be such a bad profession, I guess. Sounds better than "nightsoil collectors".
Electric fence...been there..done that..still tend to curl into the fetal position at the memory..
Gunner
"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown
Well, both ducks and frogs say 'quack', (kwak in dutch) so it could be true.
;-)
It goes the other way: To get through the holes, the frequency would need to be much higher than 2450 MHz.
The rule of thumb is that the wavelength of the radiation in question must fit into a hole in the metal sheet. The higher the frequency, the shorter the wavelength. The relevant equation is that the product of frequency and wavelength equals the speed of light.
So, for 2450 MHz: (2450*10^6)(wavelength)=3*10^8 meters/second, so wavelength= 0.122 meters, or 4.8 inches diameter. Actually, there will be significant energy leaking through if a half wavelength fits, so the issue really starts at about 2.4 inches. The cutoff function is complicated near one wavelength.
Joe Gwinn
The issue with CRTs is that the glass dielectric, having been kept at many tens of kilovolts for years, will store charge deep in the glass, and this charge cannot be eliminated quickly. The phenomena is called "dielectric adsorption" or "soakage". One can short such a CRT for a week, remove the short, and see the voltage magically spring back. So leave it shorted.
Big capacitors can do this as well, especially the big oil-paper capacitors used in HV power supplies. These can store a lethal jolt.
This same phenomena is used in Electret microphones, where a thin layer of teflon stores the HV charge needed to make the microphone work.
Joe Gwinn
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