Is it worth having a magnetometer? For what?

[pelanj]

I have a possibility to get an old OGF-L Eastern Germany manufactured magnetometer for less than 200 Eur. Is this particular model usable? What would one use such a magnetometer for? Can I detect cavities, or does it only sense iron? If yes, how to differentiate a cavity/previous settlement from iron? Thanks for clarifications

[pelanj]

How big iron things can be discovered with a magnetometer? Is it easy to differentiate deep iron from almost surface iron? Any practical experience?

Would it be possible to find old paths in the woods, etc?

[Guenter]

Yes, it is usable, if the calibration screws are not damaged! First, try to learn " What is a foerster magnetometer". At least a OGF-L is a nice but bulky piece of metal detector for mine detection and similar things. Only pure metal (iron), Bigger and deeper, the better (hammers, mines, motors, canisters etc...). No caveties detection at all. Old paths ( defined by human smell? or what?) ? The price is ok. But the calibration is time consuming.

[pelanj]

Hi, then it is not that much useful for me. I want to detect abrupt changes in ground mineralization to detect underground cavities or disturbed ground. Some old paths can be detected as changes in ground.

[Guenter]

I want to detect abrupt changes in ground mineralization to detect underground cavities or disturbed ground. Some old paths can be detected as changes in ground.

These kind of changes are best detected with a GPR (ground penetration radar). Changes of dielectric constants are good reflectors for GPR-use, like cave-detection (limestone/air/water), water cavities (mud/water or limestone/water), roman-road-detection (mud/pebble) etc... I did that with great success... but its not a 200 Euro device. Previous settlements can also be detected (bricks, ovens, waste pits) with a magnetometer like protone magnetometer, but not with an OGF-L.

[pelanj]

Thanks,that is exactly what I need to know. So I need a proton magnetometer for that.A gpr is definitely out of my budget.