English: The agency radio station with the codename Libuše (parachute drop Silver A) carried the technically correct designation Mk.VI subversion C and was transported in a Mk.III case. The radio also contained a receiver, which was inadequate, so the agency radio was retrofitted with a commercial receiver manufactured by the American company Hallicrafters, type SX24Skyrider Defiant (this receiver is not pictured). The Mk.VI radio was developed in the UK between 1941 and 1942, produced in versions A to D, and only a few dozen of these radios were made in total. The station operated in the 3 to 7 MHz frequency band in CW(A1) telegraph operation only, with a stated power of 20 to 25 W. The outer shell of the agency radio was an oak box (492 x 318 x 162 mm); the front panel was made of Pertinax; the chassis was made of copper and galvanized sheet metal; the beams and mounting bars, angles and fasteners were made of brass; the rear cover with ventilation holes was made of vulcanfibre plate. The components were of American origin, as were the controls on the front panel.