PPRuNe Forums - Weather radar effect on birds??

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- - Weather radar effect on birds?? (https://www.pprune.org/tech-log/365593-weather-radar-effect-birds.html)

It is possible to 'hear' microwaves, so even if weather radar doesn't put birds away, a device that repels birds might be possible.

http://en.wikipedia.org/wiki/Microwave_auditory_effect

Quote:

Microwave auditory effect
From Wikipedia, the free encyclopedia

The microwave auditory effect, also known as the microwave hearing effect or the Frey effect, consists of audible clicks induced by pulsed/modulated microwave frequencies. The clicks are generated directly inside the human head without the need of any receiving electronic device. The effect was first reported by persons working in the vicinity of radar transponders during World War II. These induced sounds are not audible to other people nearby. The microwave auditory effect was later discovered to be inducible with shorter-wavelength portions of the electromagnetic spectrum. During the Cold War era, the American neuroscientist Allan H. Frey studied this phenomenon and was the first to publish (Journal of Applied Physiology, Vol. 17, pages 689-692, 1962) information on the nature of the microwave auditory effect; this effect is therefore also known as the Frey effect.
Dr. Don R. Justesen also published Microwave and Behavior at The American Psychologist (Volume 30, March 1975, Number 3)
Research by NASA in the 1970s showed that this effect occurs as a result of thermal expansion of parts of the human ear around the cochlea, even at low power density. Later, signal modulation was found to produce sounds or words that appeared to originate intracranially. It was studied for its possible use in communications but has not been developed due to the possible hazardous biological effects of microwave radiation. Similar research conducted in the USSR studied its use in non-lethal weaponry.
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That auditory info is interesting, because there was an A.D. on the early 737-300, where a 180 Hz pulse repetition frequency from the X-band Wx radar was leaking in the power/signal wiring over to the nose localizer antenna and causing a false signal.

GB

I talked to a former RAF pilot who flew Hawker Typhoons over Europe. When German radar controlled anti-aircraft guns were tracking them, pilots would hear a series of clicks in their headsets and within seconds the 88mm shells were coming their way.

You try walking around on the flight deck on a ship with a "mag loop" talking headset on! If you can count fast enough, you not only clearly get the scan rate of the ships radar, but its PRF as well! :eek:

Worked in an AEW radar workshop for a while. Big bits of kit them. Hook it up to a dummy load, insert pies in waveguide, Tx for 3 - 4 sec, red hot pies ready for lunch! :ok:

Only snag, get distracted at the critical moment - Tx for 5+ sec and the cry of "Who's burnt the ******* pies?" went up!!!! Oh, and whatever you do, do take 'em out the tin foil before you try this one at home folks!!!!

For info, this technique worked on any pie - not just chicken! Never did try a full Sunday roast tho! ;)

H 'n' H

The typical safety zone for a modern weather radar is approx 9ft , in the modern litigation society would any manufacturer quote any safety zone that was not absolutely safe ???...I doubt it ...If birds did get anywhere near that they and the aircraft are in big trouble!!!!!

Quote:

A37575 . . . "When German radar controlled anti-aircraft guns were tracking them, pilots would hear a series of clicks in their headsets and within seconds the 88mm shells were coming their way."

Too much radiation, or perhaps just ambitious imagination may be playing tricks on your mind; but no German [Krupp] anti aircraft 88mm guns were "radar controlled" during WWII. :ooh:

Not the 88mm..that's right but i think they had AA 105 mm that were radar controlled....

I quite believe those anecdotes... a lot of electronics will "detect" a radar at appreciable distances.

All that's needed is a lack of shielding and something non-linear, like a diode, a transistor, a mixer tube in a radio receiver....

When I had a car without a cassette player, I took my home cassette player along, lying on the seat. It would "beep", matching scan rate and prf, whenever I drove past the local airbase, with the radar at least half a mile away.

And I remember playing with a tiny dish (10" or so) from a surplus Hunter gun-ranging radar. Just a diode in the waveguide, and a few stages of audio, and it would pick up aircraft weather radars 20 or so mile away.

CJ