Hello You want the elevated radials as high as possible. 3 meters is probably as low as you would want. 5 meters would probably be optimum.
To be effective, the radials would need to be resonant, and you would need at least two, preferably four. The current on each radial should be equal. Any vegetation under the radials may have some effect. Hopefully the corn is down and harvested before the 160 meter DX season starts. As was suggested, the K2AV folded counterpoise, when installed as Guy suggests, is a good compromise that has enabled many hams to get on 160 Meters when they are in locations that are not radial friendly Peter K1ZJH _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector