AR9285 not see n-channels

I have
# uname -a
FreeBSD beastie.mydomain.local 10.0-CURRENT FreeBSD 10.0-CURRENT #1
r243259: Mon Nov 19 09:28:08 MSK 2012
root_at_beastie.mydomain.local:/usr/obj/usr/src/sys/W_BOOK  amd64
 # grep ATH /usr/src/sys/amd64/conf/W_BOOK
options         ATH_ENABLE_11N
options         ATH_DEBUG
options         ATH_DIAGAPI

pciconf
ath0_at_pci0:5:0:0:        class=0x028000 card=0xe016105b chip=0x002b168c
rev=0x01 hdr=0x00
    vendor     = 'Atheros Communications Inc.'
    device     = 'AR9285 Wireless Network Adapter (PCI-Express)'
    class      = network


# ifconfig -v wlan0 list channel
Channel   1 : 2412      MHz 11b          Channel   7 : 2442      MHz 11g ht/20
Channel   1 : 2412      MHz 11g          Channel   8 : 2447      MHz 11b
Channel   1 : 2412      MHz 11g ht/20    Channel   8 : 2447      MHz 11g
Channel   2 : 2417      MHz 11b          Channel   8 : 2447      MHz 11g ht/20
Channel   2 : 2417      MHz 11g          Channel   9 : 2452      MHz 11b
....

wi-fi router have and enable n-mode (linksys e4200)
How to turn on or activate n-mode?