I am using a D-Link DWL-2200AP access point connected to a 250mW amplifier and a 15db omni antenna. Sitting in a building 25 feet away, netstumbler is getting a SNR of 45, but it drops to 13 every other second. Even when I remove the amplifier and antenna and leave it with its standard 5db omni, I'm still getting rather large jumps (10-20db) in my SNR occurring every few seconds. Is this a hardware problem or an interference problem? My access point is set to channel 11 and netstumbler does not pick up any other access points on or near that channel. Thanks in advance for any help.

David