Richard Harrison wrote:
Where there is a conjugate match in the transmitter-antenna system, it
exists at every pair of terminals.

Quoting w2du's web page:
“The Conjugate Theorem also shows that in a sequence of
matching networks it is necessary to match at only one
junction *if the networks are non-dissipative*. In actual
practice, since there is usually some dissipation, it
is frequently desirable to adjust at more than one point.”
--
73, Cecil http://www.w5dxp.com