User's Manual

Exalt Communications, Inc.
EX-5r Installation & Management
5000007 52
2006-05-17
at a significantly greater rate than the designed long-term performance. Consult the path design
engineer for more information about link reliability expectation 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 will indicate 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
needs to be returned 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 will provide
advice regarding the rest of the radio system and RF path engineering and environment, and
advise steps that may be taken to troubleshoot the system.
End-users should get first-line support from 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. Troubleshooting will be much more expeditious if the professional
installer and/or link designer is able to review the system in-person and review the management
information from the radio’s GUI. In turn, if the professional installer and/or link designer
contacts Exalt Customer Care, the process to rectify the system will normally be much more
expedient.
6.3 Improper RF Cable Termination
Improper RF cable termination is a very common problem. In many cases, this will be a problem
that occurs during installation, and not a problem that will suddenly appear. 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 will reduce 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 will be enough to see if this is the issue. If reduction of output power clears the
error condition, this is the likely cause.
A reflectometer, or meter that can read voltage standing wave ratio (VSWR) at the operating
frequency (5250-5850 MHz) can be used to identify poor terminations as well as poor antenna
feeds.
• The Praxsym VSWR meter is an excellent tool for this purpose