The original thing posted is useless in a car... The others concequently weren't much better either. You may get away with it if you put them behind a glass but then your tint if you have it will likely kill the reception.
Get a real pole type 12" (or less) and enjoy.
also consider something like this:
http://cgi.ebay.com/ws/eBayISAPI.dll...766532632&rd=1
Just remember that USB is very limiting when it comes to networking and nothing can replace the good old CAT5 cable. I am curious what you are using if you have only usb... that doesn't sound right unless it is a table PC or something like that.