Trango Broadband M2400S - Manual (Page 36)

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 with
polarization horizontal. Furthermore, the Base ID is 1234
and the MAC address is 00 01 DE 18 6A 05.