Basil Burgess wrote:
It apparently tunes the antenna down to an SWR of 1.5, ...

An antenna tuner doesn't change the SWR between the tuner
and the antenna. If it's 100:1 before the tuner does its
thing, it is still 100:1 after the tuner does its thing.
The extra feedline losses are caused by that unchanging SWR.
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73, Cecil http://www.qsl.net/w5dxp