Site planning
PTP 450 Configuration and User
pmp-0815 (August 2015)
4-11
Wind loading
Ensure that the site is not prone to excessive wind loading.
Antennas and equipment mounted on towers or buildings subjects the mounting structure
to significant lateral forces when there is appreciable wind. Antennas are normally
specified by the amount of force (in pounds) for specific wind strengths. The magnitude of
the force depends on both the wind strength and size of the antenna.
Calculation of lateral force (metric)
The magnitude of the lateral force can be estimated from:
Force (in kilograms) = 0.1045aV
2
Where:
Is:
a
surface area in square meters
V
wind speed in meters per second
The lateral force produced by a single PTP 450 at different wind speeds is
Table 41
Lateral force – metric
Larget surface area
(square meters)
Lateral force (Kg) at wind speed
(meters per second)
30
40
50
60
70
0.066
6
11
17
25
34
0.084
8
14
22
31
43
0.270
25
45
71
102
138
Calculation of lateral force (US)
The magnitude of the lateral force can be estimated from:
Force (in pounds) = 0.0042Av
2
Where:
Is:
A
surface area in square feet
v
wind speed in miles per hour
Table 42
Lateral force – US
Larget surface area
(square feet)
Lateral force (lb) at wind speed
(miles per hour)
80
100
120
140
150
0.71
19
30
43
58
67
0.29
7.8
12
18
23
27
