Yaesu G-1000SA, Руководство пользователя, Страница: 6 / 16

G-800SA/G-1000SA User Manual Page 4
T
OWER
-M
OUNTED
A
NTENNAS
In the preferred tower-mounting configuration, the antenna Wind Load-
ing Area must be
less than 2 m
2
( G-800SA ) or 2.2 m
2
( G-1000SA ),
and the “
K
” factor (see below) must not exceed
180
(
G-800SA
) or
230 ( G-1000SA ), where K = [ Antenna Turning Radius (m)] x [ Antenna + Mast Weight (kg)].
Refer to the antenna manufacturer’s specification sheet for determining the turning radius and weight of the antenna.
In this example, mount the following antennas stacked on a 6 kg mast.
(1) 14/21/28 MHz 5-element Yagi of Turning Radius 5.6 m, Weight of 26 kg, and Surface area 0.7 m
2
(2) 50 MHz 5-element Yagi of Turning Radius 2.6 m, Weight of 4.5 kg, and Surface area 0.3 m
2
Note: In such “Christmas Tree” installations, compute the mast weight separately for each antenna, using the relative
heights of the antennas to apportion the mast weight.
The antenna system K factor, then, is the sum of the three antenna K factors:
K
1
= K factor of 14/21/28 MHz 5-element Yagi.
K
1
= Turning Radius (5.6 m) x Weight (26 kg + 3 kg) = 162.4
Antenna Weight Mast Weight (6 kg/2)
K
2
= K factor of 50 MHz 5-element Yagi.
K 2
= Turning Radius (2.6 m) x Weight (5 kg + 3 kg) = 20.8
Antenna Weight Mast Weight (6 kg/2)
K TOTAL = K 1 + K 2 = 162.4 + 20.8 =
183.2
The antenna system Wind Loading Area is: 0.7 m 2 + 0.3 m 2 =
1.0 m
2
The Wind Loading Area (
1.0 m
2 ) is within the specifications for the G-800SA and G-1000SA , but the net K factor
( 183.2 ) can only be met by the
G-1000SA
. Therefore, the above antenna system should only be mounted using a
G-
1000SA .
We recommend that your antennas/mast should not exceed 60% of the maximum rating, to ensure a
safety margin.
Antenna Considerations
Example
Note: Installation of a Thrust Bearing
such as the GS-065 does not allow the
elimination of the mast weight from the
K -factor calculations above.
Advice
Mast Bearing GS-065 (option)
MODEL
Wind Loading Area
“K” Factor
G-800SA
2 m
2
180
G-1000SA
2.2 m
2
230
Sq. Ft
1
2
3
4
5
6
Sq. Ft
13
14
15
16
17
18
m 2
0.093
0.186
0.279
0.372
0.465
0.557
m 2
1.208
1.301
1.396
1.486
1.579
1.672
Sq. Ft
7
8
9
10
11
12
m 2
0.650
0.743
0.836
0.929
1.022
1.115
Sq. Ft
19
20
21
22
–
–
m 2
1.765
1.858
1.951
2.044
–
–