User's Manual

05-3946A01, Rev. C TransNET OEM Integration Guide 15
Antenna System Ground
Precautions should be taken to assure the antenna and its support structure are
bonded to a good earth ground system to minimize the impact of voltages
created by lightning and atmospheric charges.
CAUTION: Safety grounding systems are beyond the scope of this manual. Below you will find
some elementary advice. These are generalities; every location and installation is
unique and requires a unique safety grounding system design. Please consider con-
sulting a radio system engineer or other professional for advice on ground system
design. A well-designed ground system will minimize risk of electrical shock to
personnel and the chances of equipment damage.
Antenna Selection—Choose an antenna that offers a “DC ground” or direct
low-impedance ground connection for all metallic components. This will
allow static charges on the antenna system to be safely dissipated to ground.
It will also provide a low-impedance path to an earth/safety ground in the
event of a lightning discharge.
Support Earth/Safety Ground—The structure that supports your antenna
system should have a large-gauge ground wire that goes as directly as
possible to a safety/earth ground system. If a tower is used, it should have its
own ground system. Do not use the building’s AC-power supply ground as a
safety ground for lightning protection.
Chassis Ground—Connect a safety/earth ground to the ground post
provided on the electronic/electrical equipment. If a ground terminal is
present, bond the chassis to the safety ground at a point that is as close as
possible to the antenna system and primary power entry points on the chassis.
5.0 PERFORMANCE OPTIMIZATION
After the basic operation of the radio has been checked, you may wish to opti-
mize its performance using some of the suggestions given here. The effective-
ness of these techniques will vary with the design of your system and the
format of the data being sent.
Complete instructions for using the commands referenced in this manual are
provided in “RADIO PROGRAMMING” on Page 33.
Table 6. Length vs. loss in coaxial cables at 2400 MHz
Cable Type
10 Feet
(3.05 Meters)
50 Feet
(15.24 Meters)
100 Feet
(30.48 Meters)
300 Feet
(91.44 Meters)
LMR-400 0.70 dB 3.50 dB 6.61 dB Unacceptable Loss
1/2 inch
HELIAX
0.35 dB 1.73 dB 3.46 dB 17.3 dB
7/8 inch
HELIAX
0.20 dB 0.99 dB 1.97 dB 9.85 dB
1-1/4 inch
HELIAX
0.15 dB 0.73 dB 1.45 dB 7.50 dB