Pat Hawker's Technical Topics

摘要

A revived 'backyard Range' feature, devoted to amateur radio and SWL projects, in the professional IEEE Antennas & Propagation Magazine, (February 1996) includes an outline of 'An experimental 5.7GHz SSB Communications System' by Richard Campbell, KK7B, of Michigan Technological University. The system has a transmitter output power of only -6dBm (0.25mW) but sufficient for line-of-sight communication between two similar units of over 16km with an antenna system that provides approximately 23dBi gain. Two 0.5m aluminium dishes are used with the feed shown in Fig 1. The feed support structure is UT-085 semi-rigid coax, and the feed is attached to the dish through an SMA male-male barrel connector, in the centre of the dish. It is stated: "This makes it very easy to remove the feed for repairs, after the tripod falls over in a small puff of wind.