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arnold wilkins carried out of theoretical , practical work proved radar work.

watt wrote committee saying death ray extremely unlikely, adding:

the letter discussed @ first official meeting of tizard committee on 28 january 1935. utility of concept evident attending, question remained whether possible. albert rowe , wimperis both checked maths , appeared correct. wrote asking more detailed consideration. watt , wilkins followed 14 february secret memo entitled detection , location of aircraft radio means. in new memo, watson-watt , wilkins first considered various natural emanations aircraft - light, heat , radio waves engine ignition system - , demonstrated these easy enemy mask level undetectable @ reasonable ranges. concluded radio waves own transmitter needed.

wilkins gave specific calculations expected reflectivity of aircraft; received signal 10 times strong transmitted one, such sensitivity considered within state of art. reach goal, further improvement in receiver sensitivity of 2 times assumed. ionospheric systems broadcast 1 kw, commercial shortwave systems available 15 amp transmitters (about 10 kw) calculated produce signal detectable @ 10 miles (16 km). went on suggest output power increased as ten times if system operated in pulses instead of continuously, , such system have advantage of allowing range targets determined measuring time delay between transmission , reception on oscilloscope. rest of required performance made increasing gain of antennas making them tall, focusing signal vertically. memo concluded outline complete station using these techniques. design identical ch stations went service.