How could a discussion of spectrum mgmt be complete with talking about dynamic frequency selection? We are a coastal community and an occasional ship that fires up its radar (we think) makes one of our outdoor links go nuts hopping around. I'm wondering whether indoor LAN equipment will be effectively shielded from the radar pulses that trigger DFS. I know that most contemporary wi-fi gear includes the UNI-II band where DFS is in effect.
It's less likely that you will experience radar indoors, but still possible with certain military radars if the radar is close or has high output power.
With the Cisco 3500 AP, the DFS radar detection is done using the CleanAir spectrum analysis technology, which has a very low false detection rate. So, if the 3500 actually registers a DFS channel change, then you are very likely dealing with a real radar on your channel, and the law requires your WiFi network to clear the channel.
5 GHz weather radars near cities and airports are also ever-increasing, but Cisco WiFi equipment does not occupy these channels, and you are further protected by Cisco's best-in-class false detection performance.