Specifications

Summit WM Technical Reference Guide, Software Version 5.3 95
8 Altitude AP antenna selection
You can select the antennas to be used by each radio for the Wireless 802.11n AP model Altitude 450.
The default antenna selection is to use all three antennas for each radio. This feature will enable the use
of single band antennas.
NOTE
A radio must not be allowed to transmit into an antenna that is not designed for the operating band of the radio for
the following reasons:
• The antenna is not tested at those frequencies and therefore may produce results that exceed the regulatory limits.
• The antenna will have very poor efficiency and the power consumed by the corresponding amplifier will be simply
wasted.
When installing a single band antenna, the radio operating in the other band must be disabled so that it
does not transmit into that antenna.
As the number of antennas that are used is reduced, the MIMO performance is also reduced. For
instance, using 2 Tx/Rx antennas would reduce the separation between spatial streams but would still
be compatible to two spatial streams, so that the 2 Tx/Rx antennas will obtain up to 130Mbps in a
20MHz channel or 300Mbps in a 40MHz channel.
When using 1 Tx/Rx antenna, multi-spatial streams are not possible; the Altitude AP will provide much
lower throughput than when using 2 or 3 Tx/Rx antennas.