Users Manual

MDS 05-6399A01, Rev. G MDS™ Master Station 133
Fresnel Zone Boundary
where:
F
n
= Fresnel zone boundary in meters
d
1
= distance from one end of the path to the Fresnel zone boundary (in kilometers)
d
2
= distance from the other end of the path to the Fresnel zone boundary (in kilometers)
D = total path distance (d
1
+d
2
) in kilometers
ƒ = frequency in GHz
n = Fresnel zone, 1 (for 1st) is used here
Theoretical Signal Strength
where:
RSSI= signal strength at the receiver in dBm
EIRP = RF power output in dBm + G
ta
–L
tfl
D
fs
= free-space path loss in dB
G
ra
= receive antenna gain in dBi
L
rfl
= receive feedline loss in dB
L
tfl
= transmit feedline loss in dB
G
ta
= transmit antenna gain in dBi
Probability of System Fading
where:
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
F
n
nd
1
d
2

fD
--------------------
17.3
=
R
S
S
I
E
I
R
P
D
–
fs
G
ra
L
rfl
–
+
=
FProb ab6.010
7
–
fd
3
10
F
–


10
e
uuuuuu=