When I run inSSIDER it show the max rate for the airport extremes at 195Mbps which is sort of what I'd expect
However the 7800N is only showing 36Mbps, Its N capable right ?
My settings are in the screen shot below (deleted the Mac and SSID - you can never be sure

Wireless security is WPA2 AES
Any ideas why I'm only seeing 36Mbps