Problem with my wiress internet adapter (BT voyager 1055)

Since yesterday my connection speed has dropped from 48 Mbps to 11-1Mbps (it now varies alot more).

Can't think of why this might happen because I haven't changed anything. Downstairs, at about 10 metres away I have my BtHomeHub which is relatively new and has been working fine and still is. One of the broadband speed check websites say it's downloading at a speed of about 700kbps on the downstairs computer which is connected through cable to the router.

However, on my computer it hardly reaches 200 kbps since this wireless connection speed has dropped. I can't figure out what's wrong. The connection strength is: Very Strong just as it was before.


The problem I have with this is that the internet just disconnects from time to time on my computer and makes me unable to play any online games and load web pages.

Would be grateful if you could help,
Thanks

 

I think I know what the problem is but I still can't fix it .

My brother re-installed the wireless adapter in another USB slot on the computer. Previously, when all was working fine, the adapter was plugged into a self-powered USB hub.

I am now worried that it's not getting enough power, and that's why I have all these disconnects. I've tried to plug the adapter into one of the hub's USB slots but the computer doesn't pick it up ((.

My USB hub is: F5U231 Hi-Speed 2.0 Tetra Hub


EDIT: At the moment, after I restart the computer and plug in the device, it starts at 54 mbps then over the course of 30 seconds it decreases to 11mbps from where it oscillates.

 

how old is the wireless AP youre using? because what it sounds like is someone took an 802.11b card into an area that has 802.11g. this dosnt happen in new networks, but in older networks this did cause a problem. i doubt this is whats happening here but it sounds like it. the 11mbps isnt just a random number.
but heres what im talking about. if everyone is running an 802.11g card maxing out at 54mbps, and someone would bring an 802.11b card in, all wireless would drop down to that speed. now im pretty sure this has been corrected with the newer equipment these days.
youre saying youre using a USB hub? thats old school. what are you using for a wireless AP?