Re: Could this device be built?

Nike HIPAR, 10.4 MW, pulse width 6 microseconds.

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Jim Pennino

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10.4 * 10**6 * 6 * 10**-6 = 62.4 watts average power.

Hawk 2nd generation tracking HPIR CW RADAR AN/MPQ 39 power seems to have not yet been revealed publicly. It has been publicly stated that the AN/MPQ

39 power output level exceeded that of the earlier AN/MPQ 33, which was 125 watts. This is a vast understatement!

You forgot to allow for the PRT.

The HIPAR average power was 26 kW.

The LOPAR was 1 MW peak, 1.3 microseconds pulse width, 650 W average.

The Hawk was OK when it worked instead of digging trenches while chasing jack rabbits around McGreggor Range.

I heard the latest generation of Hawk doesn't do that.

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Jim Pennino

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The array radars on the F-22 and JSF are reported to hit gigawatts peak, and may one day get into the terawatt range. That would be enough to fry the electronics on any current-generation missile or plane, and maybe leave tanks and ships dead and immobile. And make stealth planes un-stealthy at 100 mile ranges.

BAE is developing some of the laser-fired switches that make the peak power.

John

powers.

A gigawatt at what pulse repetition rate; 1 pulse per hour?

It may be near a gigawatt ERP, but I doubt that's watts RF into the antenna.

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.

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Jim Pennino

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powers.

As the temperature rises due to frequency increase, the "lines of polarizability" begin to destabilize to the point where M becomes zero because the thermal energy is greater than that supplied by the internal field. More than *one* waveguide, then.

that

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What temperature rise due to what frequency increase?

This sounds like babble to me.

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Jim Pennino

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that

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powers.

peak

generating

Increased "pulse repetition rate" is also pulse repetition "frequency".At a high enough repetition rate(frequency) a device heats up to the point where it stops becoming a wave guide and becomes a hot widget. I have made BaTiO3 waveguides, among others.What did *you* mean by "waveguide"? Leo "thanks" Sgouros

Which was?

Then it was a whole 'nuther thing compared the pulse ack that was part of the Hawk system I worked on.

Admittedly, not a lot of techs could keep the Hawk CW equipment working reliably. Many stuggled to get through their one week a month.

For openers, the Improved Hawk, which was still on the horizon when I ETS'd out, was finally solid state. The biggest detriments to the Hawk I worked on were the 100's of tubes ( about 400 in one HIPIR), and the fact that everything was Doppler which means broadband audio (30-30KHz). MTBF was about day, but only on a good day. Some subsytems were DC-coupled. There were zillions of adjustments and many had to be done several times a day.

We had two pulse radars on site, and they almost fixed and ran themselves in comparison to the Doppler sets.

At this point the whole Hawk fire control system can sit on the tailgate of a HumVee, has over twice the range, runs almost forever without maintenance, and can track zillions of targets concurrently. It is Doppler-pulse.

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

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.

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

I believe there was a radar in that class that operated next to I-75 in Sault St Marie, Michigan. Every time the antenna rotated past the freeway, you'd hear the PRF though your car radio as a "zzzzzip".

A rectangular metal tube.

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Jim Pennino

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

No shit?

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Jim Pennino

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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.

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.

;-)

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

powers.

Dunno, but high enough to be useful in a combat jet.

No, that's real power. The planes are tiled with a bunch of 4" square transmitter/antenna things, pulsing something like 100 megawatts each. Google words like hpm weapon, array radar, e-bomb, BAE, F-22.

I'd imagine lots of people would like to know that stuff.

John

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OK, you're not talking about a radar, you're talking about an EMP weapon.

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Jim Pennino

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It's apparently both. Plus it seems to be able to blast all available data to a satellite so headquarters has a full 3D view of the entire theatre, everything all the planes and drones can see.

John

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I find a combined radar/weapon in something the size of a fighter a little hard to believe.

Little problems like how do you store energy on the order of hundreds of megawatts and how do you transfer it to the RF generators in nanoseconds. Wires have inductance.

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Jim Pennino

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know that

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generating

So google it and believe what you will.

Each of the tiles apparently has local capacitive energy storage and a a laser-triggered switch that dumps the cap energy into the antenna, probably as a UWB ringing impulse. I've seen a blurred pic of the BAE switch, and it looks like a small strip of amorphous material (possibly doped diamond?) on a ceramic substrate. High peak power laser-triggered semiconductor switches have been around for a decade at least. 10KV x 10KA = 100 MW, not unreasonable if you've got G$ to spend.

Cool stuff.

John