I've set up many v2830n (sb) routers and always with good signal have been able to get connection speeds higher than 54Mbps - often in excess of 150Mbps.
Apart from one, which is starting to really annoy me.
Router has latest f/w 3.6.4.1 sb
WPA/WPA2 mixed mode, green field, 20/40, 2T/3R A-MDSU, auto channel, SSID is 3 words separated by spaces, passphrase is 10 characters with upper/lower case and numbers.
LAN settings are fairly basic 192.168.4.0/24
dhcp pool of 150 addresses
DHCP lease is maximum

I've confirmed the laptop I'm testing with can receive higher, checked with inSSIDer that the rate is 54Mbps.

What have I got wrong in the config?

Oh, PlusNet FTTC running at 72Mbps down and 20Mbps up via the BT Infinity modem connected to WAN2 - which works beautifully.

Any advice appreciated.

Many thanks

DHW

did you set it at b+g+n?? if is not at "n" may lock lower
also a longer key than 8 characters may helps
make sure the antennas are well screw tight
channel bandwidth tick 20/40
guard interval click auto
Aggregation MSDU(A-MSDU) enable
try disable Packet-OVERDRIVETM TX Burst and see if is better
try Operation Mode ... Mixed Mode

Also note some times if *rst* file was not used during the firmware update can cost issues/conflict with previous firmware

Is the inSSIDer now reporting 300MB for the 2830?

Changed to WPA2/PSK and enforced AES encryption.

inSSIDer now reports 300 Mbps, however it doens't seem to have done much with the transfer speed.

Have noticed that WPA2/PSK is a lot faster to connect and seems more stable.

Good move but also is good to change the channel if will be better ... if are many transmissions on the same channel can slow it down

mvs_it wrote: Changed to WPA2/PSK and enforced AES encryption.

inSSIDer now reports 300 Mbps, however it doens't seem to have done much with the transfer speed.

Have noticed that WPA2/PSK is a lot faster to connect and seems more stable.

Like babis3g says, interference is likely to be the problem. Set the channel bandwidth to 20mhz and try changing around the channel until you see good speeds or no packet loss when pinging across the wireless network.

Also note some times if *rst* file was not used during the firmware update can cost issues/conflict with previous firmware