http://lists.contesting.com/_topband/2007-11/msg00248.html
FCC Data: https://transition.fcc.gov/fcc-bin/amq?list=0&facid=51487
That was a very interesting read. It does make me wonder however if the radials would count against antenna length since they are not buried.
I am not a vertical radiator user in the ham world, I have a nice unit still in the box that I intend to experiment with. But, I am lazy, and do not like to install radials, thus it is in the box. That being said, there has been some discussion about elevated ground radials vs buried (or near surface) radials in QST magazine within recent months. It appears they do work.
I further wonder, if a standard for elevated ground radial were initiated, if even more accurate predictions of daytime coverage could be made. My reasoning being that it might be less susceptable to ground conductivity.
Not sure how an FCC inspector would percieve that install on a part 15. Probably the same way it could be perceived on my metal roof. Depends on the inspector/complaints/ etc.
symmetrical and horizontal elevated ground radials do not add significant radiation to the installation over a simple ungrounded elevated part 15.219 installation. you will get more radiaition from the power and audio wiring than a properly built elevated ground radial system.
the keys to non radiating elevated radial system is symmetry and horizontal mounting such as a flat tar roof with ground radials or steel roof used as a counterpoise.
if the radials are not symmetrical and horizontal they will radiate.
most fcc field agents should know this basic fact and be able to properly evaluate an elevated radial system.
you will occasionally come across an asshat like the ngyen dude in oregon who just likes to give part 15's a hard time but agents like that are far and few between thankfully.