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Afghan Bridge Update and Sad News

My question

I don't know. The MIL-STD for EEDs is MIL-STD-1576. The "safe current" (the max current/power/time for the squib not firing) listed in the spec is 1A/1W/5min. Do the bad guys use parts made to the same spec? Do you want to have to get within 24" for it to work?

A Friis equation calculator is available here:

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When you start playing with power/frequency/and antenna gain, it backs you into path loss and radiator size.

You will have a polarization mismatch (circular (presumably) to something random), and what is probably a lousy match between squib and antenna.

It would be interesting to experiment, and the task is a worthy one.

You could measure the result of your effort the way EEDs are checked on aircraft. An optical fiber coated with temperature dependent phosphor is brought into contact with the squib active element. The other end of the fiber is coupled to a flashtube and a sensor. The phosphor is flashed and the decay time of the phosphor is measured. the decay time is proportional to temperature. You hit the aircraft with 200V/meter and check the squib for a temperature rise.

Kevin Gallimore

Reply to
axolotl
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all you need to have is a tin foil beanie for protection and a satalite dish to redirect the beam back to the source.

Its the same crap as shooting down missles with lasers. All the protection needed is to coat the missle with a flashed copper film which is over 90 % reflective to a co2 laser.

John

Reply to
John

I googled and found a 1 KW amplifier good for 30 W at 24". Kewl.

Bookmarked. Thanks!

Very clever!

--Winston

Reply to
Winston

200 V/meter is only about 106 W/m^2. That'd be a pretty good radar smack on an airframe so it's certainly a reasonable level for the test you describe ... but it isn't necessarily telling here.

The Friis equation and other path loss calculations assume far field, not the case here.

The squib will be a good match to its antenna at some frequency, because Zo of a dipole depends on length /wavelength.

An xmit antenna or feed working against a reflector of about 1 sq meter will have a footprint not much larger than that at distance comparable to reflector dimensions, so if the xmtr is 1KW then there'll be power density of about 1 KW/m^2 beneath it. This need not be a parabolic reflector, could be a planar array. If the squib

  • lead separation is ca. 60 mm (length of a flashlight battery), then aperture might be ca. 3.6E-03 m^2, capturing 3.6 watts per kilowatt.
3.6 watts is more than ample to fire a cap.

Again, I don't assert that this is the best or even a viable approach, but only a politician, bureaucrat or seat-of-pants "expert" could dismiss it out of hand with arguments presented thus far. Shielding would certainly be an issue, though achieving effective shielding is not nearly as easy as it has been made out to be by most here.

I agree that some experiments would be interesting and that some investigation is merited. It's probably most likely to happen by motivated and skilled people on the ground working with a scrounged radar, a bit of expertise and more than a bit of creativity.

Reply to
Don Foreman

By the way, a 1.2 KW 2.2 GHz transmitter is not at all difficult to come by, maybe 60 bux. Look in the microwave oven department at Wal-Mart. A half wavelength at 2.2 GHz is about 68 mm, close to the length of a flashlight battery......

Reply to
Don Foreman

We've come full circle to Bill's magnetron gadget. Old but functional microwave ovens are free for the asking in my neighborhood.

--Winston

Reply to
Winston

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