Wilan VIP 110-24, Руководство оператора

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VIP 110-24 Operator’s Manual (rev E)
- 26 -
−
L
=
C
+
20log(D)
+
20 log(F)
Where:
(for US units)
 -L = loss in dB
C = 6.6 for US units
D = path length in miles
F = 2400 (frequency in MHz)
(or for metric units)
 -L = loss in dB
C = 32.5 for metric units
D = path length in km
F = 2400 (frequency in MHz)
For example, for a distance of 10 miles
−
L
=
36.6
+
20(1)
+
20(3.38)
−
L
= −
124 dB
Calculate effective radiated power (ERP) at the transmit antenna. Since the VIP 110-24 is housed in
an outdoor enclosure, there is usually no transmission line loss as the antenna is generally connected
directly to the radio connector. However, if an additional cable is used between the radio and the
antenna cable, the cable loss (attenuation) must be included in order to calculate the correct RSS
level.
WR 2411 output power = + 23 dBm
Cable attenuation = - 2 dB
Transmit antenna gain = + 17 dB
Effective Output Power = + 38 dBm
NOTE: Table 4.2 lists attenuation values for various cables.
Calculate the RSS level at the receive radio using the formula:
Where:
Pt = Output power from the transmit antenna
Lp = path loss
Gr = Gain of the receive antenna
For example, for the above system at a distance of 10 miles, with transmit output power of 38 dBm,
and a receive antenna gain of 24 dB, the equation would be:
RSS = Pt - Lp + Gr