Reg Edwards wrote:
Regardless of its other dimensions, the primary requirement of a
mismatched connector is that its length should be appreciably less
than 1/4-wavelength at the highest working frequency.

Yes, at HF the reflections from one impedance discontinuity
and the reflections from a complimentary impedance discontinuity
3 inches away almost entirely cancel each other.
--
73, Cecil http://www.qsl.net/w5dxp