Figure 5 - Fresnel Zone - Geokon 8800-2-1A Instruction Manual

3
When using GeoNet it is important to take into consideration the radio environment, and to
understand the effect that obstructions have on radio signals. Obstructions between two antennas
can cause reflections of the transmitted signal. When these reflections arrive at the receiving
antenna, they may be in or out of phase with the signal that took a straight-line path. This
reflected signal may act as constructive or destructive interference with the received signal. For
optimum performance, Geokon recommends creating as much vertical space as possible between
the straight-line path and obstacles, including the ground. Figure 5 illustrates what is known as
the Fresnel zone.

Figure 5 - Fresnel Zone

If GeoNet is deployed to a site and communication cannot be established, it may be necessary to
elevate the devices, or to move them to a location where a radio link can be established. This
may require extending the readout cable of the attached sensors.