Zeger-Abrams Inc. (ZA) proposes the use of active feedback cancellation in both the shipboard HF (2-30 MHz) transmitter and receiver systems for cosite interference suppression. The proposed approach supplements consolidation of multiple HF transmit (TX) signals onto two existing TX antennas, and multiple HF receivers fed from one existing receive (RX) antenna. ZAs approach allows for RX sensitivity down the level limited by external quasiminimum noise and intermodulation products produced by rusty bolts 0x9D in the topside ship structure when multiple high-power HF signals are being transmitted. TX output insertion loss will be greatly reduced from that in present systems. System changes required because of changes in TX or RX frequencies will automatically be rapidly accommodated.
Benefit: Successful completion of this program will allow the cosite operation of Navy shipboard HF communications with minimal number of HF antennas to be greatly improved so that the HF receivers can receive signals down to levels limited by external, not cosite, factors, even while many high-power HF signals are being transmitted. In addition there will be much less output TX loss than in present systems.
Keywords: Cosite interference suppression, Cosite interference suppression, quasiminimum noise, ultranarrow notch filter, cancellation, shipboard HF communications
