Loren, a wifi connection is no different from a network connection.
You can have multiple network connections from a computer. If you
lose the wifi connection because the signal is too weak the computer
will regard it as network cable unplugged.

By adding a USB wifi adapter to your laptop you are adding another
network to the computer. If the USB adapter picks up a wifi connection
the computer will send network traffic down that path.

I once had two internet connections on my desktop. One was connected
to a DSL line and the other to a Comcast cable. My computer sent traffics
down to two paths simultaneously. When I cruised on the web I did not
even know which path the traffic was on. I could disconnect any one
of them. The traffic on it would be switched to the other after a short
delay. I would see a small popup that said network cable unplugged.

BTW, I did have two NIC cards on the PC. One was for the DSL line and the
2nd for the cable modem.

David

--- Loren Busch <starwagen@gmail.com> wrote:

> Okay David, let me see if I have this right.  If I connect an antenna to a
> USB port and have the right software drivers to see that device as a wifi
> antenna I'll be able to see the signal from that antenna in the list of wifi
> connections that the WiFi Assistant displays and then select that signal.
>
> Can anyone point us to a website that goes into enough detail on this
> subject that reasonably knowledgable users can understand what is needed and
> how to set it up?
>  And that would get this off topic thread diverted.
>
> On Sat, Aug 23, 2008 at 9:42 AM, David Kao <dtkao0205@yahoo.com> wrote:
>
> > You do not need to disable the internal one. You can have multiple
> > network connections. Network traffic automatically falls on the one
> > that makes successful connection to a WIFI network. The other one
> > (the built-in one) will be regarded as network cable unplugged, if
> > it is unable to make a WIFI connection.
> >
> >
> >
>