Cecil Moore wrote:
Try the ARRL Antenna Book. In general, symetrical elevated
radials don't radiate. In general, ground mounted radials
are lossy.
jawod wrote:
I second this. ARRL Antenna Book:
Check pages 2-16 to 2-18 and "The Effects of Ground' which is Chapter 3.
All the answers you need are there.
Newsgroups can be helpful but sometimes only partly. A good text is
your best friend.
Learning this stuff can be a lot of fun. It can be frustrating, too.

Just last month, with four elevated 40 meter radials 6 feet high, the
antenna was about 5 dB weaker than the very same antenna with 16
radials laid directly against soil.

This basic result repeated at three different soil locations on three
different bands, 160, 80, and 40, so it is not a fluke.

In my last quick measurement on 7MHz:

16 long radials directly on the earth (no attempt to make resonant
since they have very low Q) 0dB reference

8 long radials on the ground -1.3dB reference

4 long radials on the ground -3dB reference

4 resonant elevated radials at six feet -5.6dB reference

73 Tom