Pronounced "fraynel zone." The pattern of electromagnetic radiation that is created by a transmitting station from its antenna to receiving antennas. It is in the shape of an ellipsoid, or 3D ellipse, which looks like an elongated football.
The area around the visual line-of-sight between transmitter and receiver. Radio waves disperse as they leave the antenna. Obstructions in this zone of dispersion (Fresnel Zone) attenuate the signal. In the 2.4GHz ISM band this is particularly true of objects with a large moisture content such as trees.
The Fresnel (pronounced fray-nell) zone is the area around the visual line-of-sight that radio waves spread out into after they leave the antenna. This area must be clear or else radio signal strength will weaken.
An area around the direct line between the two ends of the link that should be kept clear. See the Radio Link page.
An extra clearance zone around and in addition to the the visual line-of-sight path.
The Fresnel (fre'-nel) zone is an elliptical region surrounding the line-of-sight path between transmitting and receive antennas. Must be obstruction free for a microwave radio link to work properly.
(pronounced 'fre-nel' the "s" is silent) The area around the visual line-of-sight that radio waves spread out into after they leave the antenna. This area must be clear or else signal strength will weaken.
An elliptical area on either side of the straight line of sight that must also be clear for a long-range wireless network to work.
Pronounced fray-nel. The area around the visual line-of-sight that radio waves spread into after they leave the antenna. This area must be clear or signal strength will weaken. The fresnel zone is an area of concern for 2.4 GHz wireless systems. Although 2.4 GHz signals pass easily through walls, they do not pass easily through moisture-laden objects like trees. Objects with high water content absorb radio waves in the 2.4 GHz band. (This is why microwaves, which also use the 2.4 GHz band, cook food. Water absorbs the waves, and heat from the energy cooks the food.) The First Fresnel Zone (FFZ) is the most important. As long as the FFZ is clear of obstructions for 60% or more, then the link acts as if a clear, free-space path exists. To calculate the size of the FFZ, use the following formula: where D is the distance between the antennas in miles F is the frequency in GHz
In optics and radio communications, a Fresnel zone (pronounced FRA-nel Zone), named for physicist Augustin-Jean Fresnel, is one of a (theoretically infinite) number of a concentric ellipsoids of revolution which define volumes in the radiation pattern of a (usually) circular aperture. Fresnel zones result from diffraction by the circular aperture.