User's Manual

Exalt Communications Inc.
EX-2.4i Installation and Maintenance Manual
Page 21
MAN-002400, Revision 001
2005-12-01
measures can be taken to keep the connector clear. Extra care must be taken if the antenna is
installed during inclement weather to be certain that no moisture gets inside the antenna
connector at any time.
The antenna may be aimed at this point in the general direction required for the link. Using a
compass, a reference bearing, binoculars or any other similar device, you may point the antenna
in the right direction (generally), and slightly tighten the azimuth and elevation adjustments
enough so that the antenna maintains its general position and is safe to be left without additional
securing.
4.3.2 Transmission Line from Antenna to Egress
Most installations use coaxial transmission line for the connection between the antenna and the
radio device. Coaxial transmission line may be either solid-shield or braided-shield variety.
Solid-shield cables are more resistant to external signal coupling and interference, but are
generally stiffer than braided cables. The path or site engineer(s) should be consulted to assure
that the proper materials were chosen for the installation with all factors considered.
Generally, the thicker the transmission line, the lower the loss. So for longer runs of transmission
line, thicker cables are highly advised. However, at every frequency, there is a maximum
diameter cable that will support the operating frequency, so be certain to verify the
specifications. This should have all been determined during the path and site planning process.
In some cases, the choice of transmission line will not be coaxial cable, but instead will be air-
dielectric waveguide. This is an expensive solution and is generally not necessary, but may be
required for very long transmission line runs and/or for very long link distances and/or for
systems that require extremely high reliability.
The following is a representative sample of transmission line types that are recommended for this
radio:
• Andrew Heliax® LDF4-50, 1/2-inch solid copper shielded coaxial cable, 3.3dB/100ft.
• Andrew Heliax® LDF4.5-50, 5/8-inch solid copper shielded coaxial cable, 2.5dB/100ft.
• Times LMR-600, 1/2-inch braided coaxial cable, 4.3dB/100ft.
• Times LMR-900, 5/8-inch braided coaxial cable, 2.9dB/100ft.
• RFS LCF12-50J 1/2-inch solid copper shielded coaxial cable, 3.5dB/100ft.
• RFS LCF12-58J 5/8-inch solid copper shielded coaxial cable, 2.8dB/100ft.
For extremely long transmission lines and/or extremely long radio paths, it may be necessary to
use waveguide transmission line instead of coaxial transmission line.
It is critical that the transmission line and antenna be capable of supporting the same type of
connector, or easily adapted. Keep in mind that it can be important to minimize the number of
connectors and adaptors, so it is ideal if they match directly without adaptation. In most cases,
transmission line will allow for N-type male connectors and antennas have N-type female