User's Manual
Deployment
Trango Broadband Wireless — User Manual M2400S Rev A
Page
32
Once the SU is installed and aimed in the general direction of the AP it is time to perform an RSSI (relative
signal strength indicator) test to determine the signal strength from the AP. Now you can precisely align the SU
antenna for maximum signal strength.
Although it is possible to rely upon the subscriber unit’s LEDs for alignment, more precise RSSI readings are
available from the command RSSI.
In conjunction with the RSSI command, it is also useful to perform the APSEARCH command. This command
will tell you which AP is providing an adequate signal at the location of the SU.
AP Search
1. Ensure AP is in opmode “On”
2. Run the apsearch command to verify which AP is providing the strongest signal strength.
#> apsearch
Press [space] then [enter] to stop
1 2405 Hz 1234 DE 18 6A 05 [H: -55 dBm] [V: -75 dBm] [E: -99 dBm]
2 2415 Hz ---- FF FF FF FF [H: -98 dBm] [V: -98 dBm] [E: -99 dBm]
3 2425 Hz ---- FF FF FF FF [H: -99 dBm] [V: -99 dBm] [E: -99 dBm]
4 2435 Hz ---- FF FF FF FF [H: -99 dBm] [V: -98 dBm] [E: -99 dBm]
5 2445 Hz ---- FF FF FF FF [H: -99 dBm] [V: -98 dBm] [E: -98 dBm]
6 2455 Hz ---- FF FF FF FF [H: -99 dBm] [V: -99 dBm] [E: -99 dBm]
7 2465 Hz ---- FF FF FF FF [H: -99 dBm] [V: -99 dBm] [E: -99 dBm]
8 2475 Hz ---- FF FF FF FF [H: -99 dBm] [V: -99 dBm] [E: -99 dBm]
#>
RSSI Command for Antenna Alignment
Step 1 Telnet into the SU (while in Opmode “OFF”). Use the freq and antenna command to note current
radio settings.
Step 2 Run the rssi command. The telnet session screen will begin a continuous readout of the received
signal strength. As you read the RSSI reading, move the antenna in the horizontal and vertical planes until the
maximum RSSI reading is achieved. To allow for plenty of fade margin we recommend a continuous RSSI
reading of -78 dBm or better. An RSSI of –88 dBm will allow you to establish a wireless link, but there may not
be sufficient fade margin for reliable and continuous operation.
Example 1 has the wrong freq and antenna settings:
#> rssi
[ 1] peak -99 dBm avg -99 dBm
[ 2] peak -99 dBm avg -99 dBm
[ 3] peak -99 dBm avg -99 dBm
Example 2 has the correct freq and antenna settings:
#> rssi
[ 1] peak -38 dBm avg -80 dBm *
[ 2] peak -38 dBm avg -75 dBm **
[ 3] peak -37 dBm avg -75 dBm **
Step 3 If it is not possible to receive an adequate RSSI reading it may be necessary to reorient the AP
(up/down, left/right) to increase the output power. Or move the SU to a location with better line-of-sight to the
AP. Alternatively consider using external antennas on either the AP or SU or both.
Once you are satisfied with the RSSI reading, tighten down the SU in the optimum position. To stop the RSSI
continuous readout hit SPACE ENTER.
In this example, an AP is detected on channel 1,
polarization horizontal. Further, the Base ID is 1234, and
the MAC address is 00 01 DE 18 6A 05.