User's Manual

CHAPTER8
ANTENNASETUPS
Revised: 25 Jan 17 8-12 ESTeem Horizon Series
FresnelZone
TheFresnelzoneshowstheellipsoidspreadoftheradiowavesaroundthevisuallineofsightaftertheyleavetheantenna(see
Figure15).Thisareamustbeclearofobstructionsorthesignalstrengthwillbereducedduetosignalblockage.Typically,20%
Fresnel Zone bl
ocka ge introduces little signal loss to the link.Beyond 40% blockage, signal losswill become significant.This
calculationisbasedonaflatearth. Itdoes nottakeintoaccountthecurvatureoftheearth.ItisrecommendedforRFpathlinks
greaterthan7milestohaveamicrowavepathanalysisdonethat take
sthecurvatureofthe earthandthe topographyofthe
terrainintoaccount.
FresnelZoneRadius=72.1SQRT [(d1d2)/(F(d1+d2)]
Units
FresnelZoneRadiusinfeet.
d1andd2instatuemiles
FinGHz
Figure15:FresnelZoneDiagram