Patent ID: 7570949
Filing Date: 2009-08-04
Classification: H01Q

Abstract:
1. A shipboard communications system for providing RF communications between a ship and a communications satellite, comprising: a modem; an antenna selector switch coupled to the modem and having a first output and a second output; a first directional antenna coupled to the first output; a second directional antenna coupled to the second output; a programmable controller for each antenna; and an antenna selector logic (ASL) circuit coupled to each antenna's programmable controller responsive to the programmable controller whereby an antenna handoff occurs when an on-service antenna is moving into a blockage zone and does not occur only when an off-service antenna is coming out of blockage, and wherein the ASL circuit comprises a first NAND gate, a second NAND gate, and an inverter, wherein said first NAND gate has a first antenna input coupled to a first pull-up resistor, a second input coupled to an output of a second NAND gate, and a first antenna selector output, said second NAND gate has a first input coupled to a first input of said inverter and a second antenna input coupled to a second pull-up resistor, and said inverter has a second input coupled to the output of said first NAND gate and a second antenna selector output.