User's Manual

Date Code 20091009 SEL-3031 Instruction Manual
Installation
Overview
2.5
require a path study, a visual path inspection, and a spectrum analysis of the area to
give a good indication of how high the antenna needs to be and how good the radio link
will be.
Radio Interference
The SEL-3031 shares a frequency spectrum with other services and FCC Part 15
(unlicensed) devices in ITU Region 2 (North, Central, and South America). This radio
should not be used in Brazil or Chile due to the regulations defining frequency
allocation. Error-free communications may not be achievable in a given location, and
some level of interference should be expected.
Consider the following points when setting up your system:
➤ Using directional Yagi antennas helps to narrow the radio path and
provide the best path to prevent adjacent interference.
➤ If you suspect interference from a nearby, licensed system (such as a
paging transmitter), it may be helpful to use horizontal polarization
for all of the antennas in the network. Horizontal polarization can
help improve signal availability but will likely increase the path loss.
Horizontal polarization can provide an additional 20 dB of
attenuation to interference because most other services use vertical
polarization in these bands. Figure 2.2 demonstrates antenna
mounting for both vertical and horizontal polarization.
Figure 2.2 Antenna Polarization
➤ Multiple SEL-3031 systems can coexist in close proximity with
minimal interference as long as each SEL-3031 is assigned a unique
network address. Each network identification uses a specific hop
pattern and number of frequency zones.
Vertical Polarization
Horizontal Polarization