Most of the build it yourself wifi antenna's seem to have a N-type
connector on the metal can end.

Do most people use RG58 or is it RG59 or does the short length make it
pretty much the same. i know one is 50 ohm and the other 75 ohm.

I have a USB wifi adapter that is easy to rip of the stubby antenna.
there seems to be just one wire connected. I assume it is just a case
of desolding and then soldering to the centre of the RG58 cable. even
if it looks a bit dodgy.

I need to get up and running quite quickly.