Trango Broadband Wireless — M900S Professional Installation Guide Rev. A Draft
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4
Section 3 Antenna Alignment (Applies to SU Only)
To align the SU antenna for optimal performance, follow the procedure below.
Once the SU is installed and aimed in the general direction of the AP, it is time to perform an RSSI test
to determine the signal strength from the AP, and to precisely align the SU antenna for maximum signal
strength.
SU Antenna Alignment Procedure
1. Ensure AP is in opmode AP
2. Telnet into the SU (while in opmode “OFF”) or access the radio via hyperterminal
3. Type
command
RSSI <channel> <e>
- Example
RSSI 3 e
(chan. 3, external antenna port)
4. Telnet session screen will begin a continuous readout of the received signal strength.
5. As you view the RSSI reading, move the antenna in the horizontal and vertical planes until the
maximum RSSI reading is achieved. For short links you can expect an RSSI of –70 dBm or
better. For longer links an RSSI of –85 dBm is acceptable. Any RSSI of less than –88 dBm will
not allow enough fade margin and may be too weak for the radios to reliably maintain a quality
link.
6. 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 of the AP, or to move the SU to a location with
better line-of-sight conditions to the AP.
Once you are satisfied with the RSSI reading, tighten down the antenna in the optimum position. To stop
the RSSI continuous readout, hit SPACE, then ENTER.
Note: The RSSI LED indicators will illuminate as the signal gets stronger, providing a guide for aligning
the antenna .
