Radiation angle is essentially the same for both. Mounting it higher
will make it more immune to losses from low, nearby objects. An elevated
one will also probably receive and deliver less interference -- provided
you keep the radials well away from, and not parallel to, mains,
telephone, and other wiring.

Roy Lewallen, W7EL

Tom Coates wrote:
Given a choice between mounting the vertical on the ground with many radials
and putting it 20 feet up with four radials, which has the lower radiation
angle? What are the other likely effects on performance - noise, RFI on the
neighbors, etc.?

Tom, N3IJ