MDS MDS 9710 Series Specifikace stáhnout pdf (Strana 16)

8 MDS 4710/9710 I/O Guide MDS 05-3305A01, Rev. D

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.

Invisible place holder

Figure 6. Typical Yagi Antenna (mounted to mast)

Feedlines

The selection of antenna feedline is very important. Avoid using 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

Meters)

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

Table 5. Length vs. Loss in Coaxial Cables at 960 MHz

Cable Type

10 Feet

(3.05 Meters)

50 Feet

(15.24 Meters)

100 Feet

(30.48 Meters)

500 Feet

(152.4

Meters)

RG-8A/U 0.85 dB 4.27 dB 8.54 dB 42.70 dB

1 2 ... 11 12 13 14 15 16 17 18 19 20 21 ... 57 58

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