When doing testing yesterday in the a new floor in a building, I changed the channel of the AP from 1 to 11 due to the fact that there were a couple of other devices I was seeing on channel 1 with the AirMagnet software. I immediately noticed that my range appeared to be much less than it had been. I assumed it was due to a lot of monitoring gear and sources of interference on the floor, and just adjusted my AP count and locations accordingly, and it was OK. Today when I went to another floor; I still had the AP on channel 11, and again the range seemed substandard, although this time on a floor where I didn't expect as much signal blocking, interference, etc. I then set the AP back to channel 1, and the range that the Aironet card saw was much improved. Then as a back check, I checked the range with the Cisco 7920 phone site suvey screen, and in a room that was getting around 17-19 SN ratio on channel 11, and around 30 on channel 1 (with the PC), the phone was consistently showing an RSSI of around 40 no matter which channel.
So in conclusion, it appears the Aironet card has a harder time picking up the signal on 11 vs 1. It must be the card since the phone seemed consistent no matter which channel. I didn't test channel 6, because the customer was with me and I didn't want to waste time trying to further isolate this problem. As a result, I am going to avoid surveying using channel 11.
So, has anyone else run into this problem? I'll try testing this elsewhere when I get a chance and post any additional findings...
