In NYC in the 70's squirrels were very rare in the winter, but the lights lasted a day or two, until the neighbors had stolen half the bulbs.
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There are no squirrels in NYC. The roaches ate them all. Lenny
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Naw, the rats eat the squirrels, the roaches eat the rats.
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Either way it's inevitable who wins in the end.....Lenny
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... and LED's are very intolerant of PIV voltage. Any AC use requires diodes to block or shunt the other 1/2 cycle. I prefer the shunt method as it does not require the protection diode to have an infinite reverse resistance. Cheers, Roger
Have you ever been near, or inside a high power RADAR system? We had two at Ft Rucker in the '70s Each ran 2 MW to track aircraft around the base, and to the Gulf of Mexico. One was always being serviced while the other was in use, to reduce the chances of both being down. Both transmitters, and the high intensity RF from the antenna could kill in less than a heartbeat.
A 25 KW RCA TTU-25B TV transmitter I rebuilt used 7 KV on the plates.
You're lucky that you didn't kill yourself.
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Only the non-union roaches. The union roaches were on strike. :)
-- You can't have a sense of humor, if you have no sense.
Unless you were standing near a tightly focused beam, this is unlikely. Microwaves kill by overheating, and the first thing heated would be the outer surface of your body, which probably wouldn't be lethal. It's more likely you'd be blinded by having your corneas cooked.
anyone
You could just as well dip your testicles in a bowl of hot water for 15 minutes.
Birds would drop dead if they flew too close to that RADAR antenna, but the highest risk of death was from the high current, high voltage power supplies in tube type microwave sources. High power RADAR tubes were huge, when compared to the lowly Magnetron in an oven.
That is used when Water boarding fails. ;-)
-- You can't have a sense of humor, if you have no sense.
I think you must be talking about much newer equipment than I worked on. Long ago, magnetrons (of a different design from the ones still used in microwave ovens) were the only way to generate high peak powers, and the oscillation frequency of a magnetron wasn't very stable.
Since then, I hear that high power klystrons have been used as amplifiers in radar systems, and I believe there's a still newer tube type which is used in the latest gear.
But as you say, the power supplies are and were very dangerous, needing elaborate interlock systems to enhance safety.
The radar tale was probably meant as a warning which would have a considerable effect on most young guys!
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The system was a few yeas old in '72, when I arrived. I think those systems were custom built by Westinghouse. I worked on so many custom and semi custom items in the Army that I don't remember, almost 40 years later. The oldest I repaired was made and deployed during the Korean war. They were so called 'Portable' systems.
Not that they weren't stable. They were powered with unfilterd DC, which caused a wideband output. They are operated as a self excited oscllator when used in a microwave, and as long as the thisng is in band, the frequency or bandwitch doesn't really matter. Have you ever read the MIT Rad Lab series of declassified W.W.-II books, or Slotnik's RADAR Handbook?
I've worked with 65 KW EEV Klystrons. A Comark with three of them, on TV Ch 55 were located in Orange City Florida. They had just ordered the transmitter when Kystrodes were introduced. Today, the TV transmitters are all solid state.
Not just the power supplies. The gates to get to the RADAR antenna had multiple key switches to disable the entire system
I saw dead birds in the parking lot fairly often, for the nine months I was s tationed at that RADAR site.
-- You can't have a sense of humor, if you have no sense.
I believe you are talking about a thing called a gyrotron. Useful at 100 GHz to 300 GHz in different models and uses.
DC,
Isn't the frequency determined by the dimensions of the cavity the energy is dumped into? Or does that tune it too broadly?
The dimensions are the largest part of determining the frequency, but it can be 'pulled' by voltage. Since it isn't run in CW mode in a microwave, the oscillation has to start each time the plate voltage is high enough on the unfiltered DC supply. The magnetron is designed for the application, to keep it operating in the assigned band in this mode of operation.
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Wasn't that an Eagles song? "Bandwitchy Woman"?
If I understand your misunderstanding... "Wideband" refers to the "spuriae" generated by the unfiltered 60 Hz and its harmonics.
AKA 'Phase Noise'.
-- You can't have a sense of humor, if you have no sense.
iae"
Ah.
Can you engineer a phase lock loop into a microwave oven?
Why would you want to? Regardless, to implement a PLL, the oscillator's frequency has to be adjustable.
Why would you want to, when a YIG oscillator is better suited?
-- You can't have a sense of humor, if you have no sense.
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