"high efficiency mobile hf antenna" that must win some kind of award for
the longest oxymoron in radio speak.

Why?
Among HF mobile antennas there those that have low, medium and high effciency.
It is acategory that is limited by some 13' in height and size of the car. One
that produces most signal would be even highest efficiency than the rest of
them. No?

Yuri, K3BU.us