Exalt Communications, Inc.
r-series
Installation and Management Manual
5000007 (ETSI)
71
2007-02-12 (draft)
than the designed long-term performance. Consult the path design engineer for more information
about link reliability expectations and anticipated RSL deviation.
In addition, regular inspection of the transmission system (RF cables and antennas) and paying
close attention to changes along the path, such as construction or tree height, or new microwave
radio installations nearby, can be extremely helpful and proactive.
When link performance is very poor, alarms on the radio front panel and within the radio’s
management system indicates particular failures. Consult this manual for more information on
the specific alarms and diagnostics, or contact Exalt Customer Care for assistance.
Exalt Customer Care is primarily motivated to determine if the radio hardware is faulty and
require return for repair, and to help execute an effective and efficient repair and return process
for radio terminals believed to be faulty. However, Exalt Customer Care provides advice
regarding the total radio system and RF path engineering and environment, and advises on
troubleshooting.
End users should first contact the installer and/or designer of the system. In many cases, an in-
depth understanding of RF design is required, and on-site analysis and special test equipment,
may be necessary. Compared to phone support from Exalt Customer Care, troubleshooting is
much more expeditious if the professional installer and/or link designer examines the system and
reviews the management information in the GUI. In turn, if the professional installer and/or link
designer contacts Exalt Customer Care, the process to rectify the system is much more expedient
due to the in-depth knowledge related to the implementation and the RF environment.
Improper RF Cable Termination
Improper RF cable termination is a very common problem. In many cases, this is a problem that
occurs during installation and is not a problem that suddenly appears. However, if cables are
moved or flexed, especially near the termination points, and radio errors, changes in RSL, or
other performance issues occur, this is a certain sign of this issue.
Another relatively easy method to test for this condition is to decrease the output power of the
radio system (at each end, one end at a time). A poor RF cable termination may be reflecting too
much RF energy back into the radio system, and reducing output power reduces the reflected
energy at a faster rate than the transmitted energy towards the far end. Be careful not to reduce
the output power to the point where the radio’s threshold is reached. Typically, a reduction of
just 3 to 6dB is enough to determine if this is the issue. If the reduction of output power clears
the error condition, this is the likely cause.
Use a reflectometer or meter that can read VSWR at the operating frequency to identify poor
terminations as well as poor antenna feeds.
The Praxsym VSWR meter is an excellent tool for this purpose