"Richard Harrison"
80% or better efficiency isn`t coming from a Class A amplifier, so maybe
it comes from a Class B amplifier.

One fly in the ointment is found on page 354 of Terman`s 1955 edition:
"The theoretical maximum possible plate efficiency that can be realized
in a Class B amplifier is pi/4 or 78.5 per cent;---."
____________

No fly to those who really know this subject. They are neither Class A or B.

Those wanting to comment on modern solid-state VHF amplifier designs and
performance parameters really should research them before doing so.

We are 60 years beyond the date of this citation from Terman.

RF