High-Capacity, Long-Range, Over Ocean Microwave Link Using the Evaporation Duct

This communication reports the first ever use of the over ocean evaporation duct to implement a high-capacity radio link from the Australian mainland to the Great Barrier Reef (GBR), North Queensland, Australia. Conventional long-distance radio communication techniques such as high-frequency (HF) radio, satellite, or cell phone are either too slow or too expensive to operate continuously in this situation. A microwave radio link overcomes these problems but would generally not be viable due to the limited range possible with a standard line-of-sight microwave link. This communication shows that by properly choosing the antenna height and operating frequency though, it is possible to trap signals in the ocean evaporation duct and substantially extend the propagation range. A 78-km link that operates at a frequency of 10.6 GHz and provides a data rate of 10 Mb/s has been established to verify the technique. The communication also provides preliminary results of the measured performance of this link and a comparison with existing radio propagation models.