Users Manual

WiBAS OSDR-Hub & Terminal Station / WiBAS-Connect Terminal Station
Start Up & Commissioning Manual - Edition 5.1
41
Antenna Alignment, Continued
RSSI best
value
definition
The RSSI (voltmeter reading) best value is defined as below:
NEGATIVE sign RSSI:
Example: The best value between -0.456 Vdc and -0.789 Vdc is:
-0.456 Vdc.
POSITIVE sign RSSI:
Example: The best value between 0.456 Vdc and 0.789 Vdc is:
0.456 Vdc.
WiBAS-OSDR
terminal
station RSSI
measurement
calculation
formula
The RSSI measurement based on the following calculation:
voltemeter receive value (in volts) x 100 = - dBm
For example:
If during alignment the voltmeter receives 0.513 volts then the calculation is the
following: 0.513 x 100 = -51.3 dBm.
So the receive signal level is equal to -51.3 dBm
Beyond the above calculation you must check the SNR value to verify that the
receive level is correct.
If the receive signal level is -51.3 dBm the SNR should be a valid
value i.e 30 dBm.
If the SNR value is a negative number means that the receive
signal level is incorrect and the alignment must be continued.
WiBAS-
Connect
terminal
station RSSI
measurement
calculation
formula
WiBAS-Connect device is capable to measure QI (quality indicator) value.
The QI value is based on the combination of RSSI and SNR measurement
values using below formula:
QI=RSSI*0.25 + calculatedRSSI_fromSNR*0.75
For cases without interference, QI is expected to be equal to RSSI.
For cases with interference, QI measurement value is showing lower values
than RSSI.
Available QI thresholds to QI table on page 93.