Why do i lose bandwidth over wireless connection?

I have virgin XL up to 20mb. i have done a speed test with an ethernet wired connection & get 14mb download, which I think is great. However when i go through my wireless router Belkin WNR1000 N150 the speed drops down to 5mb. the wireless card on my laptop is only 802.11, so i konow i can only expect 11 meg at most, but why am i only getting five? I've tried moving the router in to different places and even right next to it, but to no avail, any ideas?

Wireless is 2-way (duplex), so 1/2 of 11 Meg = 5.5 Meg?

There could be other wireless router in the area. Your router has to pick up every wireless packet that's flying around and examine it to determine whether or not it's one of yours. That will slow your wireless connection down.

Open up your wireless settings, look through the list of available wireless access points, make a note of what channel each one is broadcasting on and then choose a channel for your access point that's as unique as possible. Bear in mind that only channels 1, 6 and 11 are completely distinct from each other and all the in between channels overlap, i.e. if there are several APs using channel 11 then choosing channel 10 won't help, but 6 will.

Slightly off-topic, but If you need higher bandwidth elsewhere in the house and you can't rely on wireless then you should try Ethernet powerline adapters.

In reply to a post by jakeperks:

There could be other wireless router in the area. Your router has to pick up every wireless packet that's flying around and examine it to determine whether or not it's one of yours. That will slow your wireless connection down.

It'll most likely be this. When I moved out of a crowded flat building and into my house, I got a pretty decent speed increase, even when it was the same over ethernet. I had no idea why until my techie friend explained it like that -- it's the same as trying to work with hundreds of distractions; they all take away from your main objective.