MDS 05-4846A01, Rev. C
SD Series Ref. Manual (Packet & Transparent Mode)
15
Invisible place holder
Figure 13. Typical Yagi Antenna (mounted to mast)
Feedlines
The selection of an antenna feedline is very important. Poor quality
cable should be avoided as it will result in power losses that may reduce
the range and reliability of the radio system.
Table 4, Table 5, and Table 5 show the approximate losses that will
occur when using various lengths and types of coaxial cable in the 200,
400 and 960 MHz bands, respectively. Regardless of the type used, the
cable should be kept as short as possible to minimize signal loss.
Table 3. Signal Loss in Coaxial Cables (at 200 MHz)
Cable Type
10 Feet
(3 Meters)
50 Feet
(15 Meters)
100 Feet
(30.5 Meters)
200 Feet
(61 Meters)
RG-8A/U
0.26dB
1.27 dB
2.5 dB
5.07 dB
1/2 inch HELIAX
0.06 dB
0.38 dB
0.76 dB
1.6 dB
7/8 inch HELIAX
0.04 dB
0.21 dB
0.42 dB
0.83 dB
1-1/4 inch HELIAX
0.03 dB
0.16 dB
0.31 dB
0.62 dB
1-5/8 inch HELIAX
0.025 dB
0.13 dB
0.26 dB
0.52 dB
Table 4. Signal Loss in Coaxial Cables (at 400 MHz)
Cable Type
10 Feet
(3 Meters)
50 Feet
(15 Meters)
100 Feet
(30.5 Meters)
200 Feet
(61 Meters)
RG-8A/U
0.51dB
2.53 dB
5.07 dB
10.14 dB
1/2 inch HELIAX
0.12 dB
0.76 dB
1.51 dB
3.02 dB
7/8 inch HELIAX
0.08 dB
0.42 dB
0.83 dB
1.66 dB
1-1/4 inch HELIAX
0.06 dB
0.31 dB
0.62 dB
1.24 dB
1-5/8 inch HELIAX
0.05 dB
0.26 dB
0.52 dB
1.04 dB
