Cisco Aironet 1600 Deployment Manual page 37

Cisco Aironet Access Point Deployment Guide
Note: Avoid using single‐band (single‐radiating element antennas) like those used with the earlier AP
3500, because they are not fully compatible with the newer AP 1600/2600 and AP 3600. Antennas for
the AP 1260 and the AP 3500 are single‐radiating element antennas made for each individual band. The
AP 3600, 2600, and 1600 use dual‐band, dual‐radiating element antennas and are branded with an
orange marking. (See Figures 46 and 47.)
When using 802.11n rates in areas with high metal, such as distribution areas or airport hangars, lower
gain antennas on the ceiling may perform better because they tend to radiate the signal in all directions
and increase the chance that multi‐path will enhance the signal. If you have a clear path, a patch
antenna at the end of an aisle at roughly the same height or just above the (WLAN client) is preferred.
(See Figure 49.) Be sure to do a site survey.
Figure 49: Importance of Site Survey in Areas with High Amounts of Metal
A high gain antenna may have a null or dead spot directly below it because the antenna element is often
much longer and has less metal surface area available to conduct the radio wave if you are directly
underneath it. (See Figure 50.) The further away you are from the antenna, the more surface is
available, and the better it performs.
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