Frequency management in the forest industries radio communications

Modern trends in uhf communication systems indicate an ever increasing use of greater numbers of channels, higher transmitter powers, and decreased antenna spacing. This all adds up to an ever increasing number of systems interference problems. In most instances, a system can be rendered "interference free" by adding sufficient selectivity between the receiver or transmitter and its antenna. This added selectivity can be acquired by the use of a new low-loss tunable filter employing two high-Q, aperture coupled, resonant cavities in tandem. The physical construction of these equipments, as well as operating characteristics, will be discussed in this paper.