Aircraft radio equipment

The authors describe a number of aircraft radio sets of a more recent construction. Power supply for sending and receiving units is derived mostly from generators airscrew driven, though the modern tendency is to drive generators off the engine shaft. The sets are provided with filter units to eliminate the bad effects of h.f. generator ripple, and the engine ignition system has often to be very elaborately shielded to reduce interference With a wave-length of 45 m. and at a flying height of 6000 ft. the mean radius for the transmitters described is about 100 miles with a fixed aerial. With a trailing aerial even a small transmitter for private aircraft is described as having a radius of 200 miles under similar conditions.