Sal M. Onella wrote:
I have two HF radios, (Kenwood TS-120, TS-870) and I often observe the
forward power climbing as I manually tune and reduce the reflected power.

This is normal operation not necessarily associated with
foldback. As the tuner is tuned closer to a Z0-match,
more and more reflected power is redistributed back
toward the antenna. Although not often done, one could
conceivably tune the system by monitoring the forward
power on the antenna side of the tuner and tuning for
a maximum. It's a conservation of energy thing. Maximum
forward power to the antenna = minimum reflected power
toward the source. Who says the tuner has no effect at
the antenna?
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein