Having installed backtrack a year or so ago, i always had an issue with my external wireless adapter
Alfa AWUS036H
The problem was that after i had successfully connected to my network, after a minute or so the connection would just completely drop.. but it would still tell me that i was connected to the network.

I have now found a 'Permanent' fix for this issue:

Firstly, make sure your Alfa AWUS036H is connected to your pc/laptop.

Now open a new terminal and type the following:

Code:
ifconfig wlan1 down
or wlan0, whichever your card is on. use "ifconfig -a" to find out

Then type:
Code:
iw reg set BO
This sets the country code to boliva so you can use the alfa card in max power.

Then type:
Code:
iwconfig wlan1 txpower 30
This sets your card to 30db which is the max power the card uses

Then type:
Code:
iwconfig wlan1 rate 1M
This should fix the connection drop or very slow internet problem [main issue for me]

Now you are almost done, just type the following:
Code:
ifconfig wlan1 up
Now just open your network manager and connect to your network and the problem should be fixed.