[TowerTalk] Sizing connectors

[Jan Ditzian]

I have some lengths of hardline that were given to me, and some of them 
have N connectors on the ends. I know that these fetch a price worth 
fetching on the used market, and I do not necessarily want to use the 
N-connectors, since I use the hardline as feedline for antennas no 
higher in frequency than 10 meters.  I would like to know what I should 
measure to determine the size cable that these fit.  What diameter is in 
question when I hear the terms 1/2-inch or 3/4-inch hardline?  The 
diameter of the cable that these are on, including the outer insulation, 
is about 5/8-inch. 

I actually have several questions:

   1. Where would I measure the dimension that defines the size of the
      connector?
   2. What size hardline do I seem to have?
   3. Is there a reasonable guess as to the impedance of this line?

Thank you,

Jan, KX2A