Microwave radio relay is a technology for the transmission of digital signals and analog signals, such as telephone calls, television programs, and computer data between two locations using microwave links on a line of sight radio path. The microwaves are transmitted between the two locations along the microwave links using directional antennas. The requirement of a line of sight for the microwave link limits the distance between the two locations up to maximum of about 50 kilometers.
Microwaves along the microwave link between the two locations have extremely narrow beams. This narrow beam has the advantage that the narrow beam is confined to a line of sight path from the one location to the other location and the microwaves do not therefore interfere with other microwave equipment. The narrow beams are also an advantage for the transmission of maximum power. Similarly, other ones of the microwave links nearby can use the same frequencies, as the microwave links will not interfere with each other. The antennas used in such microwave link systems must be therefore highly directional. The highly directional beam of the microwave link may reduce the risk of interference, but it does complicate the alignment of the radio beams in the microwave link between the two antennas. The direction is highly sensitive to the positioning of the antenna and, in particular, to the positioning of any reflectors in the antenna.
The issue of aligning microwave antennas is known, for example from U.S. Pat. No. 6,836,675 (Zhang), which teaches a method for aligning antennas during the installation of microwave communications systems. A computerized link quality mechanism monitors the link quality of the link during the aligning of the installation. The link quality comprises the performance of the data communications status, such as the signal strength and the noise test results.
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