Allied Telesis AT-WA7500 - Manual (Page 51)

AT-WA7500 User’s Guide
51
Positioning Antennas for Antenna Diversity
Antenna diversity lets you attach two antennas to one radio to increase
the odds of receiving a better signal on either of the antennas. The
802.11b radio and the 802.11a radio feature antenna diversity. If you are
using antenna diversity, placement of the antennas is critical because
each antenna has a particular function. Antennas placed too close
together may cause interference with each other. Antennas placed too
far apart may not be able to establish two-way communications with
other radios.
To achieve optimum placement for the two antennas, you must place
the transmit/receive antenna so that it is within range of all the radios
that the receive-only antenna can hear. Note these important points:
‰ Use external antennas to achieve the recommended antenna
separation for placement of either omni or directional antennas.
‰ Position omni antennas for the 802.11b or the 802.11a radio at
least 0.61 meters (2 feet) apart.
‰ Position directional antennas so they point in the same direction.
‰ Position the antennas so that both antennas are within range of
the radios they need to communicate with.
‰ Do not position the two antennas around a corner or where a wall
is between them.
‰ Follow the recommended antenna separation precisely when
using the closest distances. Movement of as little as 3.05
centimeters (1.2 inches) may strongly affect performance. You
should choose the greatest distance possible within the
constraints of your environment.
Table 9 Recommended Antenna Separation for Antenna Diversity
Location
Recommended Antenna
Separation
Highly reflective warehouse
environment 0.33 m (13 in) or 0.64 m (25 in)
Moderately reflective warehouse
environment 0.64 m (25 in), 1.22 m (4 ft),
or 1.83 m (6 ft)
Open/Office environment 1.22 m (4 ft) to 3.05 m (10 ft)