User`s guide

MDS 05-2806A01, Rev. E.1 MDS iNET 900 Series User’s Guide 137
zone from the radio’s hopping pattern. The radio includes built-in
software to help users identify and remove blocked frequency zones
from its hopping pattern. See Page 56 for more information on Skip
Zones.
• If interference problems persist even after skipping some zones, try
reducing the length of data streams. Groups of short data streams
have a better chance of getting through in the presence of interfer-
ence than do long streams.
• The power output of all radios in a system should be set for the low-
est level necessary for reliable communications. This lessens the
chance of causing unnecessary interference to nearby systems.
If you are not familiar with these interference-control techniques, con-
tact your factory representative for more information.
Calculating System Gain
To determine the maximum allowable power setting of the radio, per-
form the following steps:
1. Determine the antenna system gain by subtracting the feedline loss
(in dB) from the antenna gain (in dBi). For example, if the antenna
gain is 9.5 dBi, and the feedline loss is 1.5 dB, the antenna system
gain would be 8 dB. (If the antenna system gain is 6 dB or less, no
power adjustment is required.)
2. Subtract the antenna system gain from 36 dBm (the maximum
allowable EIRP). The result indicates the maximum transmitter
power (in dBm) allowed under the rules. In the example above, this
is 28 dBm.
3. If the maximum transmitter power allowed is less than 30 dBm, set
the power to the desired level using the Management System.
(
Main Menu>>Radio Configuration>>RF Output Power Setpoint)
For convenience, Table 5-3 lists several antenna system gains and
shows the maximum allowable power setting of the radio. Note that a
gain of 6 dB or less entitles you to operate the radio at full power output
–30 dBm (28.7 dBm for iNET II).