Q
What is multipath and how to deal with it?
A

Multipath occurs when part of the signal being broadcasted by the transmitter is reflected by a obstacle i.e. buildings, hills, trees. The reflected RF waves travel farther and arrive later in time than the direct RF wave.The reflected wave arrives at the receiver with a slight delay than the unreflected causing the wave signals to overlap, which confuses the receiver. The desired wave is combined with many reflected waves in the receiver, even though the signal strength is high, the signal quality is poor. A good remedy is to avoid areas with to many obstacles, also using either right or left handed circular polarized antennas on both receiver and transmitter. Broadcasted signal through circular polarized antennas will change its orientation when reflected. In other words, if part of a right handed circular polarized signal is reflected it turns to a left handed circular polarized signal thus it will be rejected by the receiver with a right handed circular polarized antenna.

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