GE MDS Master Station Technical Manual page 106

ƒ = frequency in GHz
Fresnel Zone Boundary
⋅
nd
1
=
F 17.3 ------------------- -
n
fD
F = Fresnel zone boundary in meters
n
d = distance from one end of the path to the Fresnel zone boundary (in kilometers)
1
d = distance from the other end of the path to the Fresnel zone boundary (in kilometers)
2
D = total path distance (d
ƒ = frequency in GHz
n = Fresnel zone, 1 (for 1st) is used here
Theoretical Signal Strength
= –
RSSI EIRP
RSSI = signal strength at the receiver in dBm
EIRP = RF power output in dBm + G
α
= free-space path loss in dB
fs
G = receive antenna gain in dBi
ra
L = receive feedline loss in dB
rfl
L = transmit feedline loss in dB
tfl
G = transmit antenna gain in dBi
ta
Probability of System Fading
× ×
=
FP rob a b
FProb = probability of fading more than F
a = terrain factor
- 4 is used for very smooth terrain, such as over water
- 1 is used for average terrain, with moderate roughness
- 0.25 is used for mountainous or very rough terrain
b = climate factor
- 0.5 is used for a hot, humid climate
- 0.25 is used for temperate or northern areas
- 0.125 is used for a very dry climate
ƒ = frequency in GHz
d = path length in km
F = fade margin in dB
102
d
2
where:
+d ) in kilometers
1 2
α
+ –
G L
fs ra rfl
–L
ta tfl
–
7
× × ×
6.0 10 f
MDS™ Master Station
where:
– ( ) 10 ⁄
3 F
×
d 10
where:
MDS 05-6399A01, Rev. E