Installation Manual

Tsunami Multipoint Version 1.3 Installation Guide
Co-Channel and Adjacent Channel Interference
Co-channel interference results when another RF link is using the same channel frequency. Adjacent-
channel interference results when another RF link is using an adjacent channel frequency. In selecting a
site, a spectrum analyzer can be used to determine whether any strong signals are present and, if
present, determine how close they are to the desired frequency. The further removed from your
proposed frequency, the less likely they are to cause a problem.
Antennas
Antennas frequently play a key role in reducing the potential for interference. They come in a variety of
configurations that have different performance characteristics in the areas of gain and direction. Antennas
that transmit/receive in all directions are known as omni-directional, while those that transmit/receive
in one specific direction are categorized as directional. Antennas also vary in beamwidth, which is the
aperture to which they can “see” signals. Larger antennas typically provide narrower beamwidths and
can diminish interference from nearby transmitters by:
▪ Focusing RF energy from the intended destination
▪ Reducing the power of interfering sources not directly aligned to the antenna
Tsunami Multipoint Ethernet Systems use integrated directional antennas that transmit and receive a
relatively narrow beamwidth of radio energy, improving system performance by reducing the likelihood
that surrounding RF clutter will interfere with reception. The antennas with this system are directional
and cannot be detached.
Chapter 1. Site Planning 11
CPN 63179 Issue Date: 01/24/03