Weather radar in WWII aircraft
- Thread starter Jenisch
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tengu1979
Airman
Never heard of weather radars on wwII aircraft. I think it is post-war invention. Only about RAF Night targeting Radars on Lancasters that could target bombers in case of fog and smoke over target area...
davparlr
Senior Master Sergeant
According to this site, weather radar was not really developed until after WWII.
http://www.meteor.iastate.edu/~jdduda/portfolio/HistoryPPT.pdf
http://www.meteor.iastate.edu/~jdduda/portfolio/HistoryPPT.pdf
I was holding back on posting in case someone knew more. I am somewhat aware of a small snippet of information that shows it was being developed back then.
In Early 1940 the Germans tested Duppel, thin strips of aluminum foil to create radar clutter. Five strips of foil were equal to an typical Me 109. Due to its effectiveness and the fear that the enemy would use them against Germany they clamped on so much secrecy (Goering gets blamed for this but I'm not so sure) and so no counter measures were developed. However after the disastrous fire bombing of Hamburg in which the first time use of "windows" disabled German radars they needed counter measures very quickly. One of the solutions was "Wurzlaus" which was a coherent pulse doppler system, the first modified sets were deployed in only two weeks. A more developed system called Windlaus could also compensate for high altitude winds that were shifting the chaff/windows around which ultimatly was to turn into a system that could be used from aircraft to remove ground clutter called reislaus.
The technology for this came from two areas: a system to detect low flying aircraft and a weather radar system that used Doppler. I have several books on the subject of WW2 German radar by author Fritz Trenkle, he mentions the names of he Professors involved. I'm away from home so won't have a name for a few days.
I suspect that the 9cm and 3cm radars were not so good as their frequencies were chosen to avoid clutter. Sea water absorbed radar very well so coastal cities showed up very well. 3cm radar could be sensitive to wave tops, leaping porpoises which interfered with their use in finding submarine periscopes etc and might have been better at reflecting of clouds.
One reason German radar avoided developing the magnetron was this love of coherent pulses which a magnetron can't produce: it made it possible to measure ranges very accurately as well as the use of coherent Doppler to resolve moving targets. This is because the transmitter and receive are locked to the same local oscillator (a crystal in a temperature oven in WW2). There is a type of Doppler called incoherent in which the oscillator is locked to the magnetron pulse as it is sent but it isn't as good.
Clearly Doppler is useful in weather radar.
In Early 1940 the Germans tested Duppel, thin strips of aluminum foil to create radar clutter. Five strips of foil were equal to an typical Me 109. Due to its effectiveness and the fear that the enemy would use them against Germany they clamped on so much secrecy (Goering gets blamed for this but I'm not so sure) and so no counter measures were developed. However after the disastrous fire bombing of Hamburg in which the first time use of "windows" disabled German radars they needed counter measures very quickly. One of the solutions was "Wurzlaus" which was a coherent pulse doppler system, the first modified sets were deployed in only two weeks. A more developed system called Windlaus could also compensate for high altitude winds that were shifting the chaff/windows around which ultimatly was to turn into a system that could be used from aircraft to remove ground clutter called reislaus.
The technology for this came from two areas: a system to detect low flying aircraft and a weather radar system that used Doppler. I have several books on the subject of WW2 German radar by author Fritz Trenkle, he mentions the names of he Professors involved. I'm away from home so won't have a name for a few days.
I suspect that the 9cm and 3cm radars were not so good as their frequencies were chosen to avoid clutter. Sea water absorbed radar very well so coastal cities showed up very well. 3cm radar could be sensitive to wave tops, leaping porpoises which interfered with their use in finding submarine periscopes etc and might have been better at reflecting of clouds.
One reason German radar avoided developing the magnetron was this love of coherent pulses which a magnetron can't produce: it made it possible to measure ranges very accurately as well as the use of coherent Doppler to resolve moving targets. This is because the transmitter and receive are locked to the same local oscillator (a crystal in a temperature oven in WW2). There is a type of Doppler called incoherent in which the oscillator is locked to the magnetron pulse as it is sent but it isn't as good.
Clearly Doppler is useful in weather radar.
