Reg Edwards wrote:
The reflected volts and amps, in conjunction with the existing volts
and amps, present to the generator an impedance which causes it to
deliver to the line exactly the power in the load plus the power lost
in the line. That this occurs is quite obvious.

A tuner will present the designed-for impedance to the
generator and thus develops reflection gain that neutralizes,
to varying degrees, the reflection loss at the load.
--
73, Cecil http://www.qsl.net/w5dxp