Owen Duffy wrote:
. . .
Frank, in the absence of information on the balun, I did model it as
ideal, and that the load at the load end of the coax was 4200 ohms.
That is probably a reasonable assumption.

Perhaps the 4200 ohms is reasonable, but the assumption that the balun
is ideal when connected to that load impedance is most definitely not.
Any result you get when using that assumption is useless.

A real balun would not perfectly isolate the transmission line from
drive so influencing feed point impedance , and would probably
transform the real feed point impedance to something different to 4200
ohms, and so the line losses could be different (better or worse).

A real balun would do all those things, in addition to adding reactance
and, at that impedance level, loss.

. . .

Roy Lewallen, W7EL