The problem I have is how to represent the 1/4 piece of coax on 4NEC2. A
piece of transmission line seems to have to be connected to a "wire" at
each end and I get an error if I just have one hanging in free space where
the feedpoint is.

I am aware I can do it at the Smith Chart output but I'd prefer to be able
to graph actual Z/SWR.

Thoughts?

Cheers Bob VK2YQA/WA5

Bob, I don't know much about quad loops, so not sure what you are doing. Is
the 1/4 wave coax just to transform the single loop input impedance to a
lower value? I think a loop has about 120 ohm input Z, so 1/4 wave 75 ohm
coax transforms it to near 50 ohm.

The transmission lines in NEC are ideal, so you will not get any loss as
with a real transmission line. You do have to have a piece of wire at each
end. The loop end wire is the loop, and the feed point end wire must
contain the NEC source.

Do I have the right idea, or am I completely out to lunch?

Regards,

Frank