Ed,

You might have expected the feedpoint impedance to be around 70 ohms. It
will depend on the feedline configuration, because you haven't taken much
is the way of measures to decouple the feedline.

Your measured fwd and ref indicates VSWR~=1.5 which is consistent with 70
ohms, but you haven't measured 70 ohms.

Assuming though that such an antenna should be close to 70+j0 at
resonance...

If you did want to incorporate an impedance matching system that doesn't
compromise the portability you have described, you could try a twelfth wave
transformer with 29.3° of 50 ohm coax from the feedpoint, then 29.3° of 75
ohm coax then any length of 50 ohm coax to the transmitter.

For example, for 146MHz, that could be 137mm of Belden 9258 (RG8/X) then
139mm of Belden 1189A (RG6/U) then any length of 50 ohm coax to the tx.

Owen