A 180 or 190 degree vertical radiator presents a few different problems compared to one 90 degrees long, due to the high voltage at the feedpoint. You can have ground loss there, but since it is more of a coupling problem than a return current problem, the earth shield is usually a copper mesh that extends out around the pier about 20 feet. Think in terms of the loss at the ends of an inverted V when the ends are anchored near the ground.
Since the feedpoint is high voltage, the way in which the base of the radiator is insulated becomes more important, and the ball gap must be adjusted accordingly, and access to the area kept more secure to prevent casual contact with the excited base of the radiator. If a concrete pier is used to hold a ceramic base insulator, the pier must be bypassed with copper ground strap so it is not part of the voltage gradient between the mesh and the radiator, as concrete is conductive. For ham (in my opinion) none of this is worth the trouble, and I'd go with a quarter wave antenna. 73 Rob K5UJ _________________ Topband Reflector Archives - http://www.contesting.com/_topband