Reg Edwards wrote:
The internal resistance of a transmitter is NOT 50 ohms. It is not a design
feature. It is whatever happens to appear after the designer has met a
series of other requirements. The designer himself does not know what the
internal resistance is unless, out of curiosity, he bothers to measure or
calculate it.

Proving that, like 50/60 Hz AC power, efficiency may be
more important than maximum power transfer. Edison actually
thought that AC generators would burn up while trying to
deliver maximum power. That's why he backed DC.
--
73, Cecil, W5DXP