User Manual

MDR2400/5800-SR, Orion2410/5810-SRi and Orion 5825-SR
862-01881 Issue 12c Page 41
5. Secure the antenna.
6. Measure the RSSI level and record the value (see section 5.6).
7. Compare with the value with that calculated for the link i.e. using the path loss
calculation done when planning the link.
Typical Version 2 MDR OU RSSI Voltage vs Received
Signal Power (5.8GHz)
0.4
0.6
0.8
1
1.2
1.4
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30
Received Signal Power [dBm]
Outdoor Unit RSSI
Voltage
Figure 7. Typical Version 2 MDR5800 and Orion5810i RFU RSSI Voltage as a
function of RF input power level
-80 dBm Average 0.436 ± 0.029 V : MIB RSSI 95 ± 1 dBm (see comment below)
-30 dBm Average 1.333 ± 0.047 V : MIB RSSI 54 ± 2 dBm (see comment below)
The front panel RF Link LED, the Received Signal Strength Indicators (RSSI : on
NMS, via SNMP or as an Electrical signal on the RF Unit), Carrier-detect (NMS,
SNMP) and Frame Lock (NMS, SNMP) indicators are available to assist with link
installation and alignment.
NOTE 1 The MIB lists a value representative of the received signal level in [-dBm].
This value corresponds to the signal power measured in a 200 kHz BW centred at the
receive frequency of the radio.
When not in spectrum analyser mode, the Orion RFU translates the measured signal
power to a value corresponding to the wanted signal power in the receiver bandwidth.
NOTE 2 For the MDR and Orion10i RFUs, the RSSI values displayed in the MIB are
representative of the signal level measured over a 200kHz BW. Add ~20dB to the MIB
value for a wanted spread spectrum signal. The NMS / GUI will do this adjustment
automatically and will therefore always display the correct RSSI value.
NOTE 3 Due to the technique used to calculate the RSSI level of a wanted signal, the
measured RSSI level can differ from the actual value with up to ±3 dB.