rec.radio.amateur.antenna
metal dector for barbed wire fences

Anybody here have any suggestions for possible ways to detect fence wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square matrix?
Typical mounting would be on a tractor or trailer, so the detector would need
a sense of direction, ie looking outward not inward. Minimum range would be
around one foot with 4 feet probably optimum.
Typical retail metal detectors have a short range and need a metal free
environment, leaving the methods they use somewhat doubtful. Evidently, there
are detectors with seperate heads/coils and 1-5 foot ranges but, once again,
require a metal free environment.
One possible area would utilize rf antenna's, one transmiting and the other
recieving a reflection from the wire(s). A parabolic or corner reflector type
antenna maybe if not for the high frequency - two 12 inch antenna's would be
about max size and that's in the gigaherts range, which might be a problem.
Any suggestions along this line will be appreciated.

Hul