RADWIN2000D+UserManual Release3.6.00 19‐3
AntennaHeight Chapter19
19.2.6AntennaHeight
Therecommendedantennaheightrequiredforlineofsightiscalculatedasthesumthe
Fresnelzoneheightandtheboresightheight.SeeAbouttheFresnelZonebelow.Usingthe
notationofFigure 19‐1below,splittingExpectedRangeintod
1
+d
2
,theFresnelzoneheight
atdistanced
1
fromthelefthandantenna,isgivenby
Forthemostconservativesetting,wetakethemid‐pointbetweentheantennas,setting
whichgives
simplifyingto .
Theboresightclearanceheightiscalculatedas:
where .
19.3AbouttheFresnelZone
TheFresnelzone(pronounced"frA‐nel",withasilent“s”)isanellipticallyshapedconicalzone
ofelectromagneticenergythatpropagatesfromthetransmittingantennatothereceiving
antenna.Itisalwa yswidestinthemiddle ofthepathbetweenthetwoantennas.
Availability
16–10
7–
Cfactor frequency
GHz
RequiredRange
KM
3
10
ExpectedFadeM inarg–
10
------------------------------------------------------------
=
0.6
300
frequency
GHz
-----------------------------------
d
1
d
2
d
1
d
2
+
-----------------------------------------------------------
d
1
d
2
ExpectedRange
2
-----------------------------------------
==
0.6
300
frequency
GHz
-----------------------------------
ExpectedRange
2
-----------------------------------------
2
ExpectedRange
2
-----------------------------------------
ExpectedRange
2
-----------------------------------------
+
--------------------------------------------------------------------------------------------
0.52
ExpectedRange
frequency
GHz
-----------------------------------------
R
2
Mean
ExpectedRange
2
-----------------------------------------
2
+ R
Mean
–