GB917195A - Radiation warning system - Google Patents

Abstract

917,195. Radio transmitting apparatus. VAKUTRONIK VEB. Jan. 6, 1960, No. 455/60. Class 40 (5). [Also in Group XL (b)] A radiation warning system comprises two radiation detectors respectively sensitive to high and low levels of radiation and a transmitter transmitting signals, modulated by the output from one or other detector according to the radiation level, to a central receiving station. The transmitter valve V 2 is normally cut-off by a bias B 2 , but when radiation falls on Geiger counter Z, the output pulses therefrom overcome the bias and random pulses are ransmitted. If the counting rate increases above 2,000 p.p.s., the pulses no longer have sufficient amplitude to overcome bias B 2 and consequently cease to modulate the transmitted signal. Above this radiation level, the current from an ionization chamber I is sufficient to overcome the negative bias on valve V 3 and to cause the relay A to open and close repeatedly, modulating transmitter V 2 with regular pulses about three times the amplitude of the Geiger counter pulses. The receiver comprises an A.M. detector, coupled to a counter which may provide a printed or photographic record. A plurality of detector stations may be provided, switched on in sequence by an electromechanical clock, the results being received at a single receiver.