A Transistor Marker Beacon Receiver

Junction transistors and diodes are used to replace tubes and relays in a newly designed one-light marker beacon receiver. Ten transistors and three diodes are combined in a dual conversion superheterodyne receiver circuit which draws less than one watt of power and which has a sensitivity of 500 ¿v. Pass-band selectivity is 80 kc minimum at the 6-db down points and less than 300 kc at the 60-db down points. Dual conversion is used to transform the radio frequencies to a low IF for stable receiver gain. A three-light adapter has been developed utilizing seven junction transistors, two diodes, and miniature LC filters. The unit is the same size and weight as the one-light receiver. The weight of the entire three-light system is less than two pounds. The total current drain, from a 27.5-volt direct current supply, is less than 80 ma. A printed circuit board in a wrap-around case mounts most of the components in a design that withstands shock and vibration without the use of a shock mount.