Tropospheric scatter propagation in the low-VHF band

In 1989, an experimental investigation into short-range meteor-burst communication (<300 km) was initiated by the Hull-Warwick Communication Research Group (HWCRG) with the objective of characterising the propagation medium and developing design guide-lines for practical radio systems to exploit this mechanism. An operational meteor-burst transmitter located at Newbury and having a frequency of 47 MHz was monitored at the University of Hull for a period of several months. Over this range (approximately 300 km) it was found that the dominant propagation mechanism was not meteor-burst, but tropospheric scatter. This low-frequency tropospheric scatter phenomenon has also been noted by other workers. The experimental configuration employed in the HWCRG tests, the results obtained simultaneously at different ranges and frequencies, the modelling problem and the implications for practical beyond line-of-sight (BLOS) communications system design in the low-VHF band (30-70 MHz) are described.<>