Allied Telesis AT-WA7501 - Manual (Page 51)

AT-WA7500 and AT-WA7501 Installation and User’s Guide
51
Other Access
Points
Access points that are configured for the same frequency and that are in
the same radio coverage area may interfere with each other and decrease
throughput. You can reduce the chance of interference by configuring
access points at least five channels apart, such as channels 1, 6, and 11.