I'm having the same problem. I've tried mixed g and n, mixed b and g and n, and n only. My devices will show up in "802.11n" mode for a little bit in the Wireless>Status tab, but will frequently drop down again to g or b depending on the distance from the router. Even on "802.11n only," the modes will drop to "802.11b" or "802.11g." This is really starting to bother me because all of my devices are wireless N capable but the router won't just allow them to use only 802.11n. I mean, that was the entire reason i bought a wireless N router; to get greater range and faster speeds. Please if anyone can solve this problem it would be greatly appreciated. Thank You.
Jacob
Wireless Network Settings
802.11 Mode: 802.11n only
Enable Auto Channel Scan: Checked
Channel Width: Auto 20/40 MHz
Visibility Status: Visible
Advanced Wireless
Transmit Power: High
Beacon Period: 100
RTS Threshold: 2346
Fragmentation Threshold: 2346
DTIM Interval: 1
WLAN Partition: Not Checked
WMM Enable: Checked
Short GI: Checked
Status>Wireless>Number of Wireless Clients: 1
Mode: 802.11g
Rate: 54M
Signal: 25%