I think I am beginning to understand your use of 'source' at the antenna
end rather than the familiar transmitter end of the line.

By considering the transmission line as simply a means of transporting
RF to the antenna feed point, it can be convenient to disregard the line
and simply view the antenna system itself with a source at that feed
point. Analysis of the antenna itself actually becomes easier.
Transmission line characteristics can be dealt with later after an
understanding of the antenna is gained.

My apologies and thanks to you.

John