Page 199 - Integrated Wireless Propagation Models

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M a c r o c e I P r e d i c t i o n M o d e I s - P a r t 2 : P o i n t - t o - P o i n t M o d e I s 177

where he is either he or he as appropriate. he should be 5 m or greater. The total distance
m
b
between the antennas and their respective horizons is d L = d Lb + d Lm · The value of 8e b
(radians) can be obtained as
0.0005
d
8 = [ ( L Sb - 1 )tJz - 4 h ] (3.4.2.5)
e
e
1 3 .
b
b
dL Sb dLb
The sum of the elevation angles 8, is
d
8, 8 , + 8, m or - 9 (3.4.2.6)
=
b
84 5
where the larger value is selected for 8,
The angular distance for a transhorizon path is
(3.4.2.7)

where di is the distance of the transmission path in kilometers.
For computing diffraction loss, the distances d1 and d 2 to two ideal knife edges over
the horizon distances can be expressed as

(3.4.2.8)

(3.4.2.9)

and

(3.4.2.10)

where d l ' d�, and d 2 are in kilometers.
In the diffraction loss formula, the v parameters appropriate to knife edges at dis­
tances d1 and d are
2

(3.4.2.11)

(3.4.2.12)

=
with i l and 2 (two knife edges).