GE MDS entraNET 900 Technical Manual page 165

05-4055A01, Rev. E
For 900 MHz systems with cable runs of less than 20 ft/6m, an
inexpensive cable type such as Type RG-8A/U may be acceptable. For
longer runs, or for 2400 MHz systems, GE MDS recommends using a
low-loss cable type such as Andrew Corp. HELIAX
The choice of cable depends on the required length, cost considerations,
and the amount of signal loss you can tolerate.
types of popular feedlines and indicates the signal losses (in dB) that
result when using various lengths of cable at 900 MHz.
the same data for 2400 MHz systems.
Table 6-1. Length vs. Loss in Coaxial Cables at 900 MHz
10 Feet
Cable Type (3.05 m)
LMR-400 0.39 dB
1/2 inch HELIAX 0.23 dB
7/8 inch HELIAX 0.13 dB
1-1/4 inch HELIAX 0.10 dB
1-5/8 inch HELIAX 0.08 dB
.
Table 6-2. Length vs. Loss in Coaxial Cables at 2400 MHz
10 Feet
Cable Type (3.05 m)
LMR-400 0.70 dB
1/2 inch HELIAX 0.35 dB
7/8 inch HELIAX 0.20 dB
1-1/4 inch HELIAX 0.15 dB
1-5/8 inch HELIAX 0.13 dB
Maintaining Compliance at 900 MHz
(U.S.A. and Canada Only)
Table 6-3 outlines the minimum lengths of RG-214 coaxial cable that
must be used with common GE MDS omnidirectional antennas to
maintain compliance with the FCC and IC maximum limit of
+36 dBm for license-free 900 MHz systems.
Table 6-3. Minimum Feedline Length versus Antenna Gain
Antenna Gain Antenna Gain
(dBd) (dBi)
Unity (0 dB) 2.15 dBi
3 dBd 5.15 dBi
5 dBd 7.15 dBi
MDS entraNET Technical Manual
50 Feet 100 Feet
(15.24 m) (30.48 m)
1.95 dB 3.90 dB
1.15 dB 2.29 dB
0.64 dB 1.28 dB
0.48 dB 0.95 dB
0.40 dB 0.80 dB
50 Feet 100 Feet
(15.24 m) (30.48 m)
3.50 dB 6.61 dB
1.73 dB 3.46 dB
0.99 dB 1.97 dB
0.73 dB 1.45 dB
0.63 dB 1.25 dB
(RG-214 coaxial cable)
Minimum Feedline
Length (Loss in dB)
3 meters (1.0 dB)
3 meters (1.0 dB)
3.1 meters (1.2 dB)
cable.
®
Table 6-1 lists several
Table 6-2 shows
500 Feet
(152.4 m)
Unacceptable
Loss
11.45 dB
6.40 dB
4.75 dB
4.00 dB
500 Feet
(152.4 m)
Unacceptable
Loss
17.3 dB
9.85 dB
7.50 dB
6.25 dB
Power Level
at Minimum Length
+31.15 dBi
+34.15 dBi
+35.95 dBi
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