[SEDXC] METAL DETECTORS

[Tom W8JI]

Mike,

Metal detectors will normally not work on thin wires unless they contain 
significant iron. The reason is copper and non-ferrious metals are detected 
by eddy currents that decrease the detector's inductance and increase 
frequency.

To trace cables and radials I use an MFJ-259 coupled to a conductor or cable 
my a transformer, and I have a small loop antenna I walk around the area 
with using a portable receiver fed by the loop.

I can find cables a foot or more deep within inches of where they are really 
at using the loop null.

I do bury metal plates over cable crossings so I can locate them with my 
metal detectors, but tracing normal radials and wires requires RF signals.

I have pictures of how I do this, but have not written an article yet. It 
works over hundreds of feet of cable length.

This is the best method I have found, but there may be better metal 
detectors I don't have. If anyone else has a better system that **really** 
works, please answer here! By really works, I mean reliably locates small 
wires within a few inches.

73 Tom



> Anyone out there that has had experience with metal detectors?  There must 
> be thousands of models on the market and I am having trouble figuring out 
> what I need.  I want to find copper radial wire only a inch or so below 
> the ground and possible some control cables and coax further down. 
> Possibly will use it for finding other objects later.  I have been looking 
> at the White brand and would be willing to pay $300-400.  Please email me 
> directly with any input.  K4PI at Bellsouth.net 73
> _______________________________________________