Carey,
If the antenna is NOT 50 ohms (it's actually an offset multi-band dipole with a 4::1 balun transformer), or not resonant, I was thinking that the COAX would introduce some problems.
They do use small runs of COAX for matching, that's what I was thinking, that the SWR would not be constant across the length of the COAX if the antenna was not 50 ohms resonant.
I was looking for a way to put the imaginary connector to the antenna at the far end of the COAX but maybe that's not going to solve anything.
Jeff