Does that card support more then 300 Mb/s?
ROS 6.0beta3 on x86
tx-power at all rates fixed = 3/interface wireless
set 0 adaptive-noise-immunity=none allow-sharedkey=no antenna-gain=0 area="" \
arp=enabled band=5ghz-a/n basic-rates-a/g=6Mbps basic-rates-b="" \
bridge-mode=enabled channel-width=20/40mhz-ht-below compression=no \
country="czech republic" default-ap-tx-limit=0 default-authentication=yes \
default-client-tx-limit=0 default-forwarding=yes dfs-mode=none \
disable-running-check=no disabled=no disconnect-timeout=3s distance=\
dynamic frame-lifetime=0 frequency=5700 frequency-mode=manual-txpower \
frequency-offset=0 hide-ssid=no ht-ampdu-priorities=0 ht-amsdu-limit=8192 \
ht-amsdu-threshold=8192 ht-basic-mcs=\
mcs-16,mcs-17,mcs-18,mcs-19,mcs-20,mcs-21,mcs-22,mcs-23 \
ht-guard-interval=any ht-rxchains=0,1,2 ht-supported-mcs=\
mcs-16,mcs-17,mcs-18,mcs-19,mcs-20,mcs-21,mcs-22,mcs-23 ht-txchains=0,1,2 \
hw-fragmentation-threshold=disabled hw-protection-mode=none \
hw-protection-threshold=0 hw-retries=7 l2mtu=2290 mac-address=\
00:80:48:77:04:4E max-station-count=2007 mode=ap-bridge mtu=1500 \
multicast-helper=default name=wlan1 noise-floor-threshold=default \
nv2-cell-radius=30 nv2-noise-floor-offset=default nv2-preshared-key="" \
nv2-qos=default nv2-queue-count=2 nv2-security=disabled \
on-fail-retry-time=100ms periodic-calibration=default \
periodic-calibration-interval=60 preamble-mode=both \
proprietary-extensions=post-2.9.25 radio-name=00804877044E \
rate-selection=advanced rate-set=default scan-list=default \
security-profile=default ssid=SPKFree-FINtoMTS station-bridge-clone-mac=\
00:00:00:00:00:00 supported-rates-a/g=6Mbps supported-rates-b="" \
tdma-period-size=2 tx-power=3 tx-power-mode=all-rates-fixed \
update-stats-interval=disabled wds-cost-range=50-150 wds-default-bridge=\
none wds-default-cost=100 wds-ignore-ssid=no wds-mode=disabled \
wireless-protocol=unspecified wmm-support=disabled
range ~500m
