User's Guide

Appendix A. Radio Signal Propagation
User's Guide A-8 BreezeNET BU-DS.11/RB-DS.11
Clear Line of Sight
A clear line of sight exists when no physical objects obstruct viewing one antenna from the location
of the other antenna.
A radio wave clear line of sight exists if a defined area around the optical line of sight (Fresnel
Zone) is clear of obstacles.
Fresnel Zone
The Fresnel zone is the area of a circle around the line of sight.
The Fresnel Zone is defined as follows:
Figure A-7. Fresnel Zone
R = ½
√
(λxD)
R: radius of the first Fresnel zone
λ:
wavelength
D: distance between sites
Figure A-8. Fresnel Zone Clear of Obstacles