12
MDS 1710A/C and MDS 2710A/C/D
MDS 05-3447A01, Rev. F
Invisible place holder
Figure 7. Typical Yagi Antenna (mounted to mast)
Feedlines
The selection of antenna feedline is very important. Poor quality cables
should be avoided as they will result in power losses that may reduce the
range and reliability of the radio system.
Table 3
shows the losses that will occur when using various lengths and
types of cable at 200 MHz. Losses at 130-174 MHz will be slightly
lower. Regardless of the type of cable used, it should be kept as short as
possible to minimize signal loss
† Cable loss slightly lower at 130-174 MHz.
3.4 Power Connection
The transceiver can be operated from any well-filtered 10.5 to 16 Vdc
power source. The power supply should be capable of providing at least
2.5 amperes of continuous current.
The red wire on the power cable is the positive lead; the black is nega-
tive.
NOTE:
The radio is designed for use only in negative ground systems.
Table 3. Length vs. Loss in Coaxial Cables at 200 MHz
†
Cable Type
3 Meters
(10 Feet)
15 Meters
(46 Feet)
30 Meters
(91 Feet)
150 Meters
(525 Feet)
RG-8A/U
0.32 dB
1.6 dB
3.2 dB
16 dB
1/2 inch HELIAX
0.10 dB
0.49 dB
0.98 dB
4.9 dB
7/8 inch HELIAX
0.05 dB
0.27 dB
0.54 dB
2.7 dB
1-1/4 inch HELIAX
0.04 dB
0.20 dB
0.40 dB
2.0 dB
1-5/8 inch HELIAX
0.03 dB
0.17 dB
0.33 dB
1.65 dB
