An experimental 5.7 GHz SSB communications system

A SSB communications system, for use in the amateur 5.7 GHz band, is described. This system as several unique features, including the successful use of microstrip circuitry printed on low-cost FR-4 substrate, a microwave complex modulator for SSB generation, and a VHF complex demodulator for SSB reception. There are no conventional narrow-band intermediate-frequency stages. The system power output is -6 dBm PEP, and the receive system-noise figure is 11 dB. An antenna system is described that provides approximately 23 dBi gain, which is appropriate for line-of-sight communication over 16 km paths.