RADIOSONDE INSTRUMENTS A2-3 
b. The pulse modulated 403 MHz radiosonde transmits a signal at 
a nominal frequency of 403 MHz. The transmitted signal pro- 
vides meteorological data. 
c. The transponder radiosonde is a receiver-transmitter type of 
instrument. The receiver operates ona frequency of 403 MHz, 
and the transmitter operates ona frequency of 1680 MHz. This 
instrument is designed to be used with rawinsonde systems 
equipped with ranging capability. 
L368) FMH#3 
