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In sci.physics Arny Krueger wrote:

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I'd also like to know what you'd use for waveguide at those power
levels. It's hard enough to keep moderate megawatts contained and
the waveguide in one piece.

I've definately seen waveguide with holes burned in it by RF.

Particularly in Miami. It got to be old - the PAR would start failing, a
piece of waveguide might get holed, and then the water-soaked air dryer
would be towled out and reloaded with dessicant.

Waveguide size is set by the operating frequency. For X-band, the
smallest
dimension is less than a half of an inch.

If you put the right stuff in the waveguide, it still passes a signal
well
and you raise the arc-over point dramatically.

The "right stuff" is usually dry air, sometimes dry nitrogen.

I never worked around any radars that used anything more sophisiticated than
dry air. Dry air turned out to be dicy in Miami, because of the humid air.
I've heard about waveguide that was based on ceramics, I wonder if the
ceramic was the dielectric. I think that many ceramics have far higher
breakdown voltages than dry air.

Phased-array radars have very many small antennas, transmitters and
receivers. Each one handles only modest amounts of power.

No ****?

;-)

The point being, this is how really impressive power levels can be achieved
with relatively low tech waveguide, etc.