Antenna Height
Chapter 21
FA4800 User Manual
Release 1.9.30
21-3
Antenna Height
The recommended antenna height required for line of sight is calculated as
the sum the Fresnel zone height and the boresight height. See
About the
Fresnel Zone
below. Using the notation of
Figure 21-1
below, splitting
ExpectedRange
into
d
1
+ d
2
, the
Fresnel zone height
at distance
d
1
from
the left hand antenna, is given by
For the most conservative setting, we take the mid-point between the
antennas, setting
which gives
simplifying to
.
The
boresight clearance height
is calculated
as:
where .
About the Fresnel Zone
The Fresnel zone (pronounced "frA-nel", with a silent “s”) is an elliptically
shaped conical zone of electromagnetic energy that propagates from the
transmitting antenna to the receiving antenna. It is always widest in the
middle of the path between the two antennas.
Availability
1
6
–
10
7
–
×
Cfactor
×
frequency
GHz
×
RequiredRange
KM
(
)
3
×
10
ExpectedFadeM
in
arg
–
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
–
R
Mean
6367.4425
Km
=
