User Manual

Exalt Communications, Inc.
Exalt i-Series Installation and Management Guide
5000001 93
2007-06-25
Use a reflectometer or meter that can read VSWR at the operating frequency to identify
poor terminations as well as poor antenna feeds.
Note: The Praxsym VSWR meter is an excellent tool for this purpose
Multipath Propagation
Multipath propagation is a term that encompasses changes to the RF path, such as
reflections and/or refraction, causing partial or complete destruction of the radio signal,
and thus excessive bit errors and/or system outages.
Rapid changes in temperature, inversion layers, humidity, air pressure, water evaporation,
as well as standing water or moisture on objects along the path are all examples of
changes that can cause multipath propagation. New building construction near either end
of the path or along the path can cause new reflection characteristics.
If your system has been operating without issue and is suddenly experiencing issues that
are symptomatic of a certain time of day or related to change in climatic events or some
of the external factors listed above, this is likely the cause. Consult a professional RF
path engineer in these cases. Often, minor repositioning of the antennas at either or both
ends can reduce or eliminate these problems.
RF Interference
RF interference is usually indicative of another radio system nearby either end of your
radio system or aimed towards one or both ends of your radio system – usually at or near
the same frequency and usually a signal level similar to the level of the signal of your
radio system.
Other forms of RF interference also exist, such as electronic equipment placed close to
the radio chassis or transmitters that couple onto the cabling or grounding system of the
radio. Microwave ovens and wireless communication devices used near the equipment or
cabling are examples of electronic equipment interference.
Note: The EX-2.4i and EX-5i operate in license-exempt bands.
Microwave ovens, wireless Internet devices and cordless phone
technology may also use this frequency band. It may be necessary to
separate the radio chassis, cabling system and antenna from these devices.
RF interference, like most other causes of problems, is indicated by significant bit errors
and/or system outages.
One means to determine presence of interference is the use of a spectrum analyzer that
covers the same range as the radio system. A professional RF engineer can use a
spectrum analyzer to locate sources of interference, measure these sources, and determine
potential remedies to take to operate in the presence of interference.
If a spectrum analyzer is not available, the radio’s RSL port can help determine RSL
levels of interfering signals. By turning the far-end radio off, the residual RSL measured