GE GFK-2489 - Manual (Page 149)

6-16 TranSphere TS Wireless Extended Range IP Networking Transceivers – January 2008 GFK-2489
6
Aiming Directive Antennas for Maximum RSSI
The wireless network integrity depends, in a large part, on stable radio signal levels being
received at each end of a data link. In general, signal levels stronger than –90 dBm provides
the basis for reliable communication that includes a 15 dB fade margin. As the distance
between the AP and Remotes increases, the influence of terrain, foliage, and man-made
obstructions become more influential, and the use of directional antennas at remote locations
becomes necessary. Directional antennas usually require some fine-tuning of their bearing to
optimize the received signal strength. The transceiver has a built-in received signal strength
indicator (RSSI) that can be used to tell you when the antenna is in a position that provides
the optimum received signal.
RSSI measurements and Wireless Packet Statistics are based on multiple samples over a
period of several seconds. The average of these measurements is displayed by the TS
Wireless.
The measurement and antenna alignment process usually takes 10 or more minutes at each
transceiver.
The path to the Management System Menu item is shown in bold text below each step of the
procedure.
Procedure
1. Verify that the Remote is associated with an AP radio. Observe the condition of the
LINK LED.
LINK LED = on or blinking
This indicates that you have an adequate signal level for the measurements, and it is
safe to proceed.
2. View and record the Radio Retries and No Ack counts on the Radio Packet Statistics
Screen. This information will be used later.
3. Clear the Radio Statistics history.
4. Read the RSSI level at the Remote (RADIO RSSI=).
5. Optimize the RSSI by slowly adjusting the direction of the antenna and watching for a
peak in received signal strength. Get the RSSI indication several times after making
each adjustment, so that the RSSI accurately reflects any change in the link signal
strength. The higher the indication (less negative), the stronger the signal level (that is,
–60 is better than –70).