Fred W4JLE wrote:
Assuming I have an antenna that is perfect on 3.8 MHz. Perfect being
defined, as I am feeding it with exactly 1/2 electrical wave length of 50
Ohm feedline and it is 1:1 SWR measured at the source end.

What would the SWR be if I substituted the 50 Ohm feedline with a 1/2
wavelength of 72 Ohm feedline?

The head of the pin is now open for dancing...
Hi Fred, It would still be 1:1. Doesnt matter about the characteristic
impedance of the transmission line as long as you use 1/2 electrical
wavelength.
Gary N4AST