Three 20pf capacitors in parallel. A small sheet of copper is cut in triangular shape and joins the capacitor terminals and coil lug is attached to the canter of the triangle with heavy brass bolts. The input compartment of the filter is at the left. Series elements carry less current and employ wirewound coils. At right is antenna relay, with power leads bypassed as they leave the filter compartment.
Filter is set to correct frequency by adjusting the inductance of the tubing coils.
In this particular filter, the parallel circuit was affixed to the output capacitor of the pi-network tank circuit of the transmitter and does not show in the photograph. The filter is adjusted by removing the connections from the end of the half-wave sections and adjusting each section to 50mhz by spreading the turns of the coil with a screwdriver while monitoring the resonant frequency with a dip oscillator. When tuning adjustments are compleated,the straps are removed and the top of the filter box is held in place with sheet metal screws.