I have external Wireless Adapter TP Link TL-WN7200ND I'm currently using it on Windows its giving me 4/5 signal bars When I used same Adapter in Ubuntu 13.04 it gives 2/4 bars. I'm using Live USB for Ubuntu and and I'm also not sure if i have to install any drivers cause in Network Options its Showing 2 lists of Networks 1 with low signals 2nd with High (More Bars).
With this and I was able to speed 150 mb, all bars, and slow dissolves (in ubuntu 12.04.4 probe that is where I get a serious error if the adapter is connected before starting session, ubuntu freezes on that ground connecting the adapter only when session starts.)
This is the solution installed ndiswrapper, free driver add to the blacklist when ndiswrapper is installed just install the supplied driver pt-link.
To install the ndiswrapper is complicated if you have ubuntu 12.04, 12.10 and 13.04 that you will need install as the new one is not in center WILL NEED ubuntu download and install the packages you need are 4 or 5 Find them and download here packages.ubuntu.com creeo if you have ubuntu 13.10 this solved the problem this is not necessary.