ProSoft Technology ILX34-AENWG - Manual (Page 66)

PSW-PWD ♦ ProSoft Software Selecting Equipment
ProSoft Wireless Designer User Manual
Page 66 of 91
ProSoft Technology, Inc.
July 8, 2009
Net dB North America
250mW
Max. Distance
Europe
EIRP 100mW
Max. Distance
Miles Kilometers Miles Kilometers
32 11.3 18 7.5 12
35 13.4 21.5 9 14.5
37 15 24 10 16
Net dB is the gain of the antenna minus the cable loss. A 10 dB margin has been
included in the above calculations.
Wireless Path
Distance 60% Fresnel Zone Approximate Earth
Curvature Antenna AGL Height
with no Obstructions
mi km feet m feet m feet m
1 1.6 10 3 3 0.9 13 4
5 8 30 9 5 1.5 35 10.7
10 16 44 13 13 4 57 17
15 24 55 16.7 28 8.5 83 25
Additional antenna height will improve the maximum distance and will require a
Path Feasibility Study to help determine a new height. A Path Study will better
determine the appropriate antenna height and net dB gain required for a given
path. Path Study and Site Survey services are available from ProSoft
Technology.
7.2 Calculate Total Gain
The "Link Gain" is a composite of the gains of each of the antennas (the Master
antenna and the Remote antenna) as well as any cable loss. For example, if you
want to communicate over a 5 mile (8 km) unobstructed distance, you should
include at least 19 dB of Link Gain. If you are using 4 feet of cable on the Master
side and 10 feet of cable on the Remote side, you need to determine what the
cable loss is by using the previous chart.
Example:
Cable loss at the Master: 2 dB (4ft, 1.22m)
Cable loss at the Remote: 5 dB (10ft, 3.0m)
Total Cable Loss: 7 dB
You need 19dBi and you already know you will have 7dB gain loss due to
cabling. In order to ensure that you have antennas that will cover the cable loss,
the Required Gain must be added to the Cable Loss.
Required gain for 5 miles (8 km): 19 dB
Total cable loss: +7 dBi
Required gain for antenna selection 26 dB