Sub-optimal Wifi speeds

[Speedster]

I have a TL-MR3220 3G-router set up at home with a Huawei E173 for internet access. For some reason I can only get my MacBook Pro to connect at 72Mbps max, even when sitting right next to the router. I've played around a bit with the router settings (20MHz/40MHz; b/g/n) but not really seeing any difference. Any suggestions?

 

[Roman4604]

For some reason I can only get my MacBook Pro to connect at 72Mbps max

Don't think you can get any better.

In 802.11n a 20MHz channel is rated at 72Mbps, while a 40MHz channel is rated at 150Mbps. 802.11n also allows for bonding of up to 4 channels simultaneously (referred to as MIMO) for a theoretical max of 600Mbps using 4 x 40MHz channels (nothing on the market supports this yet).

Your limitation come from, firstly the AP in you're router is not MIMO capable, its rated at 150Mbps, so at best only able to send/receive via 1 x 40MHz channel. Secondly the Broadcom based AirPort Extreme adapters in Macbook's do not support 40Mhz channels at 2.4GHz, only 20MHz.

Thus your combination is only able to use 1 x 20MHz channel at a max of 72Mbps.

I have a TP-Link WA901ND 2.4GHz AP rated at 300Mbps (max 2 x 40MHz channels in MIMO) but because of the Airport limitation at 2.4GHz my Macbook Air only connects at a max of 144Mbps (2 x 20MHz channels). In contrast my Dell 6400 laptop with Intel Centrino 5100N adapter does not have the limitation, so connects to the same AP at 300Mbps (2 x 40MHz channels).

The actual real world throughput between my two laptops is however far less that the specs suggest. The Air achieves 6-8MB/s in Win file copy, while the Dell only does a little better at 7-9MB/s.

 

[Speedster]

Don't think you can get any better.

In 802.11n a 20MHz channel is rated at 72Mbps, while a 40MHz channel is rated at 150Mbps. 802.11n also allows for bonding of up to 4 channels simultaneously (referred to as MIMO) for a theoretical max of 600Mbps using 4 x 40MHz channels (nothing on the market supports this yet).

Your limitation come from, firstly the AP in you're router is not MIMO capable, its rated at 150Mbps, so at best only able to send/receive via 1 x 40MHz channel. Secondly the Broadcom based AirPort Extreme adapters in Macbook's do not support 40Mhz channels at 2.4GHz, only 20MHz.

Thus your combination is only able to use 1 x 20MHz channel at a max of 72Mbps.

I have a TP-Link WA901ND 2.4GHz AP rated at 300Mbps (max 2 x 40MHz channels in MIMO) but because of the Airport limitation at 2.4GHz my Macbook Air only connects at a max of 144Mbps (2 x 20MHz channels). In contrast my Dell 6400 laptop with Intel Centrino 5100N adapter does not have the limitation, so connects to the same AP at 300Mbps (2 x 40MHz channels).

The actual real world throughput between my two laptops is however far less that the specs suggest. The Air achieves 6-8MB/s in Win file copy, while the Dell only does a little better at 7-9MB/s.

Thanks - that makes sense. Would never have worked that out myself!