User's Manual

Tsunami MP.11 2454-R, 5054-R, and 5054-R-LR Installation and Management
Chapter 7. Troubleshooting 130
Registration Requests and Authentication Requests should be divisible by 3. WORP is designed in a way
that each registration sequence starts with 3 identical requests. It is not a problem if, once in a while, one of
those requests is missing. Missing requests frequently is to be avoided.
Monitor / Per Station (Information per connected remote partner)
Check that the received signal level (RSL) is the same on both sides; this should be the case if output power
is the same. Two different RSLs indicate a broken transmitter or receiver. A significant difference between
Local Noise and Remote Noise could indicate a source of interference near the site with the highest noise/.
Normally, noise is about –80 dBm at 36 Mbps. This number can vary from situation to situation, of course,
also in a healthy environment.
Monitor / Link Test (Information used by Administrators for on-the-spot checking)
Check the received signal level (RSL) and noise level. Compare the RSL with the values from path analysis.
If the figures differ significantly from the values recorded at the Per Station window, check for environment
conditions that change over time.
Analyzing the Spectrum
The ultimate way to discover whether there is a source of interference is to use a spectrum analyzer. Usually, the
antenna is connected to the analyzer when measuring. By turning the antenna 360 degrees, one can check from
which direction the interference is coming. The analyzer will also display the frequencies and the level of signal is
detected.
Proxim recommends performing the test at various locations to find the most ideal location for the equipment.
Avoiding Interference
When a source of interference is identified and when the level and frequencies are known, the next step is to
avoid the interference. Some of the following actions can be tried:
• Changing the channel to a frequency away from the interference is the first step in avoiding
interference. For countries that require DFS, it might be not possible to manually select a
different frequency.
• Each antenna has a polarization; try to change to a polarization different from the interferer.
• A small beam antenna looks only in one particular direction. Because of the higher gain of such
an antenna, lowering the output power or adding extra attenuation might be required to stay legal.
This solution cannot help when the source of interference is right behind the remote site.
• Lowering the antennas can help avoid seeing interference from far away.
Move the antennas to a different location on the premises. This causes the devices to look from a different angle,
causing a different pattern in the reception of the signals. Use obstructions such as buildings, when possible, to
shield from the interference.
Conclusion
A spectrum analyzer can be a great help to identify whether interference might be causing link problems on
Tsunami MP.11 systems.
Before checking for interference, the link should be verified by testing in an isolated environment, to make sure
that hardware works and your configurations are correct. The path analysis, cabling and antennas should be
checked as well.
Statistics in the web interface under Monitor tell if there is a link, if the link is healthy, and a continuous test can be
done using the Link Test.