"A loop will not require a ground pane- in fact a local ground plane
(aircraft's conductive body) is what causes quadrantal error. "



True, but an aircraft unit, anticipating a QE, already has a certain
amount of error built in, so even without a groundplane, the antenna
would still need to be swung to check for correct bearings. The beauty
of the system is that it does not rely on the interpretation of nulls
or S meter readings. It simply points directly to the station.

I cannot but think a GPS might be more accurate somehow!

Brad.