SWITCHLESS COMBINERS

A switchless combiner is a system composed of two hybrids, a variable phase shifter and a fixed length of transmission line.  A high-power switchless combiner system is used for combining the output of two parallel transmitters.  The utility of a switchless system is that either of the two transmitter outputs, or both of the transmitter outputs, can be routed to a station load for testing or maintenance without disrupting the signal to the antenna or the station load.  

This on-air switching is accomplished through a phase shifter which is capable of shifting the phase of the signals entering it by at least 180 degrees through three different positions.  The operation of the phase shifter is remotely controlled through the use of a motorized circuit which employs low-level DC control voltages and 120 V AC drive voltage.