Spatial diversity for HF remote sensors

A large volume of research has been undertaken to improve short range mesh based sensor networks. This paper considers a contrasting, but less established, research position that long range single hop HF transmissions suit many applications. HF transmissions are, however, not without challenges and this paper details an experiment to evaluate the viability of using spatial diversity to mitigate the intermittent and cyclical availability of HF circuits. Four transmitting nodes were placed across Australia and six days of packet transmissions at 14 MHz were analysed. The findings support the use of spatial diversity to maximise HF circuit availability and the presence of redundant circuits suggests the system has the capacity to accommodate antenna radiation patterns that present nulls in return for targeted gain.