Antenna Multiplexer for VHF Frequency Hopping Radios

With the use of a manually tuned transceiver multiplexer*, it is no longer necessary for each fixed frequency transceiver at an Army command site to require erection of a separate mast-mounted antenna. This has greatly increased the commander's mobility. However, these manually tuned transceiver multiplexers are incompatible with the frequency hopping ECCM technique which is to be incorporated into the next generation of VHF combat net radios (CNR). Unless a transceiver multiplexer for frequency hopping transceivers is developed, command sites will revert back to erecting a separate mast-mounted antenna for each frequency hopping transceiver. The US Army is investigating the concept and feasibility of a frequency hopping transceiver multiplexer. An approach which uses helical resonator filters, PIN diode switched capacitors and quadrature couplers for combiner and antenna matching circuits represents the most optimistic design, though its insertion loss does not meet current requirements.