John Ferrell wrote:

Here is the short version:
A matched transmission line behaves like the theory books say it does.
The rated power from the transmitter goes through the transmission
line with the lowest possible loss to the antenna where it is radiated
just like the book says.

Mismatched transmission lines also behave like the theory books say. The
rated power from the transmitter goes through the transmission line to
the antenna where it is radiated just like the book says.

I deleted only "with the lowest possible loss" because increased SWR
does increase line loss. But if the line loss is low when matched, the
increased loss due to high SWR is often negligible.

. . .

Roy Lewallen, W7EL