I'm going to install an antenna with a ground plane tube on the lower portion
(about 24 inches) Question; Is it OK to mount the antenna on the side of my
motorhome with only the antenna portion sticking up above the roof ?

Just got us a TREK with the bed that raises up to the ceiling, don't even have
to make the bed. Just be sure Cookie is out of it before hitting the switch
that makes the bedroom disappear and the living room appear.
JJ Sinclair