Wireless N speed

Hi!

0. Problem
- I have a very annoying problem with my Wireless N network speed. For a couple of months I cannot solve it because I cannot guarantee which device(s) is(are) the bottleneck(s).
- The problem is that I am not getting 300Mbps on any of my PCs in the network.

1. Hardware configuration:
- D-Link DIR-615 Router (rev B2, fw 2.25)
- Intel Centrino Wireless Advanced-N 6205
- Dell (Broadcom) DW1501
- Belkin Wireless N USB Adapter F5D8053 v3
- Belkin Wireless N USB Adapter F5D8053 v4

All the hardware is rated "up to 300Mbps".

2. Device settings
a) DIR-615 Router
- 802.11 Mode: n&g only (tried n only)
- Wireless Channel: Autoscan (tried ch8 and 11) at 2.4GHz only
- Transmission rate: Best (tried 270)
- Channel Width: Auto 20/40Mhz
- Security WPA2-AES only
- Short GI: True (tried False)
- WMM Enable: True
- Transmit Power: High
- Extra Wireless Protection: True
b) Intel Centrino Wireless Advanced-N 6205
- Maximize performance
c) Dell (Broadcom) DW1501
- 40Mhz Intolerant: Disabled
- 20/40 Coexistance: Auto
- Short GI: Auto
- WMM: Enable
- WZC IBSS Channel: 11(20Mhz)
d) Belkin Wireless N USB Adapter F5D8053
- WMM: Enable

3. Status
- I "measured" the reported router speed with an application called inSSIDer and it indicates that it can connect to 300Mbps (Also with the DW1501 Dell Utility).
- On the Intel card I get only 130Mbps
- On Dell i get only 65Mbps
- On Belkin Cards i get also 130Mbps

The speeds were reported by Windows and the distance from the router varied from ~1m to 5m during the tests.

4. Conclusion
- Is my router capable of 300Mbps?
- Are the cards all just 130Mbps?
- Is it a configuration problem?
- What is the maximum speed for each device?

Thank you.

Ok, the Broadcom (Dell) Dw1501 card is limited to only 72Mbps from construction. I found the specifications on the Dell website. Why am I getting 65Mbps and not 72Mbps on this card, though?

Tested with an Intel Centrino Advanced-N configured properly: D-link works at 300Mbps, card works at 300Mbps. So, i think the adapters are limited to 130Mbps?

I've recently acquired a F5D8053 USB adaptor. I've done a bit of digging into why only 150Mbps is achievable.

Routers using the 2.4GHz band can use a narrow (20MHz) or wide (40MHz) bandwidth. Narrow bands support 150Mbps, while wide bands support 300Mbps.

I expect when the original driver for the F5D8053 USB adaptor was released (supporting Windows 2000, XP, Vista) it supported the 40MHz bandwidth. This was before the Wireless N specification was finalised.

When the Wireless N specification was finalised, manufactures had to place "consideration" into allowing users use the 40MHz bandwidth. This bandwidth can cause problems if your neighbours are also using Wireless N.

When Belkin released new drivers for Windows 7, rather than support 40MHz, they just removed the functionality from the driver. So it'll only support 20MHz , which means it's limited to 150Mbps.

I've contacted Belkin to see what they say about this. They could make the excuse that the original packaging stated 300Mbps on Windows 2000, XP and Vista.