[TowerTalk] Full wave loop on 80m : Impedance 50 or 75 Ohms??

[Lee Noonan]

I have been using Full wave loops on 80m since 1987 and have always used 75 Ohm coaxial cable as feedline without a Balun.  I know of other hams that use a Balun on a full wave loop. My Loop is Rectangular in Shape and fed in the center of one of the shorter sides. The Antenna is terminated with a gap of around 3 inches between the ends.
This was how it was described , for a German Quad antenna which is a Full wave loop in a Diamond shape terminated at one of the sharp pointed ends..The German Quad was Quoted with an Impedance of roughly halfway between 50 & 70 Ohms Impedance.. My Quad antenna is 33 feet high at all 4 points.  Any Comments on what impedance this Antenna May be at the feed point and how to feed it with Coaxial cable... I am about to run ALL new cables thru the roof of My House and I'm wondering whether to use 50 or 75 Ohm Cable...
73
Lee Noonan  VK2LEE