User manual

E BEAM
User Manual & Modem Installation Guide
© whirlwind
Specifications subject to change without notice
14
Understanding Received Optical Power Level
Readings
Depending on where in the system the received optical power level is
being measured and the distance between the antennas, the readings
will differ slightly. The two sections below define the power level
ranges for readings at the modem and the readings obtained by the
modem utility.
Received Optical Power at the Modem
The table below displays the nominal received optical power levels at
certain distances. The actual operating range of the 100 Mbps
system is +2 to -30 dBm.
Distance (m) Power Level (dBm)
10 – 300 +2 to -12
Calculation: (# of feet * 0.3048 = # of meters)
Due to the fiber connectors and the fiber itself, there could be a loss of
up to 1 dBm in the actual reading.
* If there are problems with data transmission, and the modem seems
to be operating properly, the received optical power may be either out
of the operating range or too close to the maximum and minimum
received power thresholds. If the received power is greater than +2
dBm, it causes receiver saturation. To determine what the received
power level is, use an 850 nm fiber optic power meter to measure the
dBm value. If the received power is greater than +2 dBm, a
temporary solution is to simply disconnect the fibers connected to the
“RX” ports on the modem and connect the fiber to the power meter.
For tips about how to correct these types of problems, please refer to
the Troubleshooting Guide on page 15. When troubleshooting optical
power issues, it is recommended to use the optical power meter
instead of relying on the data provided by the software.