Cisco Cisco Aironet 1400 Wireless Bridge 설치 가이드

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

Figure 2

The RSSI voltage increases linearly with signal level.

Table 3

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.

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.

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.

Step 3

Return the antenna to the position where the signal is strongest, or where there are two similar peaks,
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