To accomplish this mission, it was first necessary to determine the types of signal communication being used by the Soviets. For both Wireless telegraphy (WT) and Radiotelephone (RT), the high frequency band was used almost exclusively, the main exception being navigational aids, i.e. radio beacons, which were used on medium frequency. Until the end of 1942, only WT traffic was found, thereafter R/T was also employed, increased greatly from 1944 onwards. The Soviets used radar only to a small extent, beginning at the end of 1944. Almost all W/T traffic was encoded or enciphered.IF-186 p. 1
