WDS 1710 Series, Техническое руководство

Страница: 17 / 62

2.3 Antennas and Feedlines
Antennas
The transceiver can be used with a number of antenna styles. The exact
style depends on the physical size and layout of the radio system. A
directional Yagi (
Figure 6 ) or corner reflector antenna is generally rec-
ommended at remote sites to minimize interference to and from other
users. Antennas of this type are available from several manufacturers.
ײª·-·¾´» °´¿½» ¸±´¼»®
Figure 6. Typical Yagi Antenna (mounted to mast)
Feedlines
The selection of antenna feedline is very important. Avoid poor quality
cables as they will result in power losses that can reduce the range and
reliability of the radio system.
Table 4 and Table 5 show the losses that will occur when using various
lengths and types of cable at 400 and 960 MHz. Keep the cable as short
as possible to minimize signal loss.
Table 4. Length vs. Loss in Coaxial Cables at 400 MHz
Cable Type
10 Feet
(3.05 Meters)
50 Feet
(15.24 Meters)
100 Feet
(30.48 Meters)
500 Feet
(152.4 Me-
ters)
RG-8A/U 0.51dB 2.53 dB 5.07 dB 25.35 dB
1/2 inch HELIAX 0.12 dB 0.76 dB 1.51 dB 7.55 dB
7/8 inch HELIAX 0.08 dB 0.42 dB 0.83 dB 4.15 dB
1-1/4 inch HELIAX 0.06 dB 0.31 dB 0.62 dB 3.10 dB
1-5/8 inch HELIAX 0.05 dB 0.26 dB 0.52 dB 2.60 dB
05-3305A01, Rev. E 9