Abstract: Circuit apparatus for interconnection between an electric power source of expected variability and an recreation vehicle requiring a known fixed range of voltage change. A voltage sensor (18) for producing signals representative of corresponding source voltage variation ranges. A transformer (60) with tapped primary (56,58) is selectively switched to provide low boost or high boost to compensate two low ranges of the source voltage connected by a relay (54) energized by the voltage sensor signals (18). If the source voltage exceeds the low boost range, a further relay (28) energized by a sensor signal connects the source voltage to output terminals (40,42) for ultimate use.

Abstract: A simple inexpensive, very effective high to ultra high frequency radio direction finder is disclosed utilizing two parallel antenna units with switching means for alternately connecting the antenna units to a conventional unmodified FM or NBFM receiver at an audio frequency rate. If the centroids of the antenna units are not on a line normal to the path of the monitored input signal, the amplitude of the audible tone output signal resulting from the difference in phase of the alternately received input signals at the time of switching will vary with the angle of deviation of the antennae from this normal position. The slight alternations of phase are demodulated as slight frequency changes and produce a tone in the FM receiver output having the audio frequency of the antenna switching device.