"Keith Willshaw" wrote in message ...
"Lawrence Dillard" wrote in message
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"Keith Willshaw" wrote in message
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"Keith Willshaw" wrote in message
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SNIP


To my knowledge the Germans never developed a true proximity
fise as they lacked the cavity magnetron and miniaturized electronics
necessary.IRC correctly the best they could manage was the "Kranich"
acoustic proximity fuze.

By the time the shipment had been readied, the German had in their
possession possibly several dozen "dud" Allied proximity fuses, recovered
from the battlefield. Gen Eisenhower had authorized the use of these
devices
over land at the onset of the Ardennes Offensive. German authorities
offered
soldiers a bounty for the recovery of partial or complete "duds". Their
analysis revealed the super-tough tubes employed therein.


More alarming was the capture of an ammunition dump that included
stock of intact unfired shells. The allies didnt know if the Germans had
seized any and so launched a crash investigation to see if jamming the
fuze was possible

However, no Allied proximity fuse developed duringWWII used the resonant
cavity magnetron. Research and development on the miniaturization of such
devices had not begun by the end of the conflict in Europe. Instead, a
radio
signal on a lower frequency was used.


The frequency used was 180 to 220 MHz according to
http://www.smecc.org/radio_proximity_fuzes.htm

Keith


At least for aerial proximity fuses the allies had already developed
jamming methods for their own fuses during developement of their own
fuses in the event that the Germans began using these type of fuses
against the Allied bomber fleets.

The fuses were triggered by a combination of doppler shift and the
intensity of the reflected wave.

Jamming involved a motor driven tuner shifting through the frequencies
used by the shells to spoof a doppler shift.

"Super tough" valves weren't the real secret to the proximity fuse.
PWB printed wireing boards were in part. The real secret seems to
have been packing the electronics into waxes and oil.