English: Resonant stub tank lines (Lecher lines) in portable 200-300 MHz UHF vacuum tube transmitter from 1938. These were part of a backpack transceiver for remote broadcasts developed by radio station KCMO in the 30s. Each pair of parallel rods constitute a length of open-circuited transmission line. They are connected to the plate circuit of the type 955 "acorn" vacuum tube oscillator and function as a high-Q W:resonant circuit to determine the frequency of the transmitter. The lefthand one oscillates around 200 MHz, the righthand one 300 MHz. The rods are 3/8 inch solid brass, spaced 3/4 inch apart, approximately 1/8 wevelength long, tuned by a trimmer capacitor near the ends/