Dual frequency feed horn for an antenna

A steerable feeder link antenna is formed of a steerable reflector and a stationary feed horn assembly. The feed horn assembly allows dual mode transmit and receive functions for circularly polarized microwaves and includes a four arm turnstile junction (4) coupled to the feed horn (3) through the feed horn's side wall to couple transmit frequencies, and an axially coupled transmission line for the receive frequencies. Each turnstile junction arm incorporates chokes to block the receive frequencies. The axially coupled transmission line's cut off frequency is above the transmit frequency to prevent transmit signals from interfering with receive signal receivers.