Features electronic sequence controlling insuring the proper sequencing of both power amplifier and preamplifier switching. The sequencer guarantees that preamp switchover occurs before power amplifier turn on by first removing the preamplifier control voltage and then providing a relay closure the PTT line of the linear amplifier. This insures that hot switching which could damage the preamp relay contacts or destroy the GaAsFET's does not occur. Low loss bias-T's are built into the sequence controller to allow the preamp control voltage to be fed to the preamp via the coax cable. No need for additional DC cable! The preamp and the PA can be controlled separately; built-in LED's reflect the status of the sequencer. Connectors: N-type for antenna cable, for control cable Sub-D.