User Manual

MDR2400 and MDR5800 User Manual
862-01881 Issue 8 Page 38
5.3.2 Alignment Procedure
1. Locate the far site and point the antenna to the antenna at the far site, as
accurately as possible using binoculars or a compass.
2. Connect the multimeter to the RSSI connector on the Outdoor Unit using the
supplied RSSI test cable and set the multimeter to measure volts.
3. Check the RSSI level and refer to the figure below for received power level.
4. Align the antenna until the maximum RSSI is attained.
5. Secure the antenna.
6. Measure the RSSI level and record the value (see section 5.7).
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 Outdoor Unit RSSI Voltage vs
Received Signal Power
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 OU 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 MIB lists a dBm value representative of the received signal level. The value
detected is representative of the level that would be measured should a CW signal be
input at the Outdoor Unit's Diplexer RF Port - a Spread Spectrum signal will appear to
be 20 dB lower. The NMS makes an adjustment for this by using a 20 dB offset
(addition to the Indoor Unit MIB-indicated value).
The front panel RF Link LED, the Received Signal Strength Indicators (RSSI : on
NMS, via SNMP or as an Electrical signal on the Outdoor Unit), Carrier-detect (NMS,
SNMP) and Frame Lock (NMS, SNMP) indicators are available to assist with link
installation and alignment.