Abstract: The present antenna system includes a phased array antenna system comprising a limiting circuit, an isolation circuit, and a phasing circuit. The limiting circuit includes a system of fast signal diodes coupled with a zener diode, which provides sharp limiting and increased limiting thresholds to received signals. In addition, the isolation circuit prevents a cable coupled to the output of the antenna unit from becoming electrically coupled with the antenna element itself. Furthermore, the phasing circuit allows the present antenna system to provide a null in a fixed direction over a wide bandwidth of signal receiving frequencies.

Abstract: A hub assembly (10) includes a hub (12) which can be attached to the mast (11) of an antenna by fastening assemblies (41) at a selected position along the mast (11). The hub (12) can carry rods (46) in horizontal slots (39, 40) to form a capacitance hat for the antenna, or can carry rods (46) in vertical slots (37, 38) so that the rods (46) can be positioned to overlie a trap (51) by a selected extent to tune the trap (51) a selected amount. Clamping assemblies (47) hold the rods (46) in the selected slots (37-40). Apertures (36) are provided in the hub (12) and are adapted to receive guy wires to support the antenna.