Range - Proxim Harmony 8569 User Manual

Troubleshooting

Range

Every environment is unique with different obstacles, barriers, materials, etc., and,
therefore, it is difficult to determine the exact range that will be achieved without
testing. Radio signals may reflect off of some obstacles or be absorbed by others
depending on their construction.
The IEEE 802.11a specification supports eight data rates: 54 Mbps, 48 Mbps,
36 Mbps, 24 Mbps, 18 Mbps, 12 Mbps, 9 Mbps, and 6 Mbps. Harmony's 2X mode
supports eight data rates: 108 Mbps, 96 Mbps, 72 Mbps, 48 Mbps, 36 Mbps,
24 Mbps, 18 Mbps, and 12 Mbps. Operation at 6 Mbps or 12 Mbps provides greater
range than operation at 54 Mbps or 108 Mbps.
By default, a Harmony 802.11a Access Point will automatically adjust the data rate to
maintain a usable radio connection with its clients. Therefore, a client that is close to
an Access Point may operate at 54 Mbps while a client that is on the fringe of coverage
may operate at 6 Mbps. Note that if you specify a single data rate for the Access Point,
you may reduce the effective range of the Harmony 802.11a products.
The Harmony 802.11a Access Point includes two integral antennas or two antenna
connectors to support antenna diversity, which can improve system reliability. Due to
the characteristics of radio waves, it is possible that one antenna may provide better
performance than a second antenna installed a short distance away. Only one
antenna is used at a time; they cannot be used simultaneously to increase the Access
Point's coverage area.
Proper antenna placement can help improve range. Here are some guidelines:
• For best results, position the Access Point's antennas so that one antenna is ver-
tical and one is horizontal.
• Place the Access Point as high as possible. In an office environment, try to place
it above cubicle walls.
• Do not place a sheet of metal (like a filing cabinet) between two 802.11a devices.
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