Cisco Cisco Aironet 1400 Wireless Bridge インストールガイド
13
Cisco Aironet 1400 Series Outdoor Wireless Bridge 28-dBi Dish Antenna
78-15547-01
Installation Notes
Positioning the Antenna Using the Received Signal Strength Indicator
The Received Signal Strength Indicator (RSSI) port produces a DC voltage that is proportional to the
received signal level. The RSSI voltage is available whenever a signal is present, regardless of the bridge
mode (installation or normal), association status, or pre-configuration. The RSSI port is a female BNC
connector on the housing (see
received signal level. The RSSI voltage is available whenever a signal is present, regardless of the bridge
mode (installation or normal), association status, or pre-configuration. The RSSI port is a female BNC
connector on the housing (see
).
The RSSI voltage increases linearly with signal level.
shows the RSSI voltage for selected signal
levels.
The voltage ranges from 0 to 2.7 volts for signals between –90 and –20 dBm, respectively. The accuracy
over temperature and component variations is ± 4-dB. You can use any convenient voltmeter to position
the antenna.
over temperature and component variations is ± 4-dB. You can use any convenient voltmeter to position
the antenna.
To position the antenna using the RSSI voltage, follow these steps:
Step 1
Remove the RSSI port cover and connect a voltmeter probe to the port. Use a probe terminated with an
BNC connector to make this connection.
BNC connector to make this connection.
Step 2
Slowly sweep the antenna to the left and right of the signal path while monitoring the RSSI voltage for
peaks in signal strength.
peaks in signal strength.
Step 3
Return the antenna to the position where the signal is strongest, or where there are two similar peaks,
halfway between them.
halfway between them.
Step 4
Secure the horizontal adjustment.
Step 5
Slowly sweep the antenna up and down while watching for peaks in signal strength.
Step 6
Return the antenna to the position where the signal level is strongest.
Step 7
Secure the vertical adjustment.
Step 8
Remove the voltmeter cable from the RSSI port and replace the cover.
Table 3
RSSI Voltage Levels
Nominal Signal Level (dBm)
RSSI Reading (volts)
–20 or greater
2.70
–30
2.31
–40
1.93
–50
1.54
–60
1.16
–70
0.77
–80
0.39
–90 or less
0.00