Fresnel Zone

July 24, 2012

CIMM DEFINITION: The radio signal width between any two antennas is not perfectly straight and uniform, as if it were a beam of light. Instead as the signal propagates away from the transmitting antenna, it widens towards the center point between the two antennas and then narrows again as it approaches the receiving antenna. This limits the usefulness of satellite dish antennas in locations where there is extremely limited open sky for signal reception. The signal path through space must be clear not only for direct line of sight, but must also be clear for the expanding Fresnel zone, which may be several meters larger in diameter than the ground-based satellite dish. (Source: