Sorry about that I should of been more clearer on what I was asking help for.
I am trying to set up a N network.
Correct me if I am wrong. A single channel is 20MHz in width and when two channels are bonded they are 40MHz in width.
It is possible to use either 20MHz or 40MHz channels with IEEE 802.11n. The two channels are known as the primary or control channel and the secondary or extension channel. The primary/control channel performs the same functions as it would in a single channel mode by sending and receiving data. The secondary/extension channel is also able to send and receive data.
This is what I meant by a extension channel.
I have seen this done in a posting by another user. Where they have chosen two channels instead of one.
Anytime you are working on wireless speed don't overlook the possibility that you are running with a old nic driver on the laptop/pc. As an example, I was getting 150mbsp with an HP laptop with Intel 5100 chip. Downloaded and installed the latest driver from intel and now get 300mbps as I would expect. This was with BS 14929 big build without any wireless tricks, just 40 for channel width selected. The driver also had a channel width selection.
Of course, as has been stated many times before, interference is probably the biggest reason for poor wireless performance.