"Cecil Moore" wrote
Adding or subtracting loading-coil degrees is what
happens while one is tuning a screwdriver antenna.
At resonance, the screwdriver is electrically very
close to 90 degrees in length.
_______________

It may have the reactance of an unloaded ~90-degree, self-resonant radiator.
But in normal applications that doesn't make a screwdriver the radiational
equivalent of that full-sized radiator, because the radiation resistance of
the physically/electrically short screwdriver whip is less than a full-sized
antenna -- and much less on the lower bands.

A dummy load can have the reactance of a resonant screwdriver, too, but a
dummy load is not a very good antenna. I doubt you would claim that it is
electrically 90 degrees in length, just because it has the same reactance as
an unloaded ~90 degree, self-resonant monopole.

That conclusion applies to a screwdriver antenna system, as well.

RF