Self-excited voltage standing wave ratio bridge

From 80 to 10 meters per band, this portable bridge has a built-in signal source in order to tune the antenna before the transmission line is connected. When the desired antenna is tuned to frequency, the oscillator is controlled by the crystal. The independent oscillator is a simplified conversion problem for each band, so only the supply voltage from J1 and the oscillator output to the header circuit needs to be converted.