Cambium Networks cnReach N500, User Manual

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cnReach N500 User Guide
Technical Reference
phn-4673_002v000 (March 2018)
3-4
Attention
RF performance is often more problematic at higher RSSI levels. When the Transmit Power
is set too high, the receiving radio RSSI may be too high and the overall noise floor in the
area will increase.
Transmit Power should be tuned to provide enough SNR on the receiving radio.
Please refer to the RSSI and Sensitivity & Minimum SNR per Modulation sections.
When lab testing with the optional 0dBi “rubber duck” antenna, it is recommended to
install 20dB coaxial attenuators and adjust the transit power to 100 mW.
RSSI
With the options of exceptional sensitivity and fast, complex modulations in one product it is important
to consider the input signal level (RSSI) of the receiving radio to ensure that it’s not too low and not too
high.
Slower less complex modulations have better sensitivity, require a smaller minimum SNR and will
therefore operate at a lower RSSI offering greater effective range.
Faster more complex modulations have less sensitivity, require a larger minimum SNR and will therefore
operate at a higher RSSI offering less effective range.
The RSSI scale below indicates the various receive signal levels in dBm and how they relate to the
sensitivity levels of each modulation.
Strong signals are often more problematic than weaker signals and should be tuned if above -50 to -
45dBm. LINKPlanner will help by indicating the expected RSSI level for a given path profile.