Magnetic field mapping

[dgd3]

Sometimes I have trouble finding a magnetic free launch area in what seems to be open land spaces.
Other than using the phantom itself is anyone aware of a low-cost way to map out an area to see where the underground pipes or whatever it is that could be causing the problem? I've tried a couple apps on iOS but they seem useless.

 

[Meta4]

Sometimes I have trouble finding a magnetic free launch area in what seems to be open land spaces.
Other than using the phantom itself is anyone aware of a low-cost way to map out an area to see where the underground pipes or whatever it is that could be causing the problem? I've tried a couple apps on iOS but they seem useless.

What tells you that a magnetic problem exists?

 

[Erised]

A cheap metal detector will help to find buried steel pipe or bars and some wires if not too deep but even ground water will cause magnetism. Dowsing for groundwater works for many, I know that for me the fork branch pulls down alot but can this affect the quad I don't know.

 

[dgd3]

What tells you that a magnetic problem exists?

Phantom won't start and lights blink. Move it a few meters and then it works. Just sometimes I have to move it a few times in what appears to be an open city park.

 

[Meta4]

Phantom won't start and lights blink. Move it a few meters and then it works. Just sometimes I have to move it a few times in what appears to be an open city park.

OK ... that's not normal in a clean site and suggests that the site has steel or electrical cables somewhere nearby, maybe buried pipes or reinforced concrete?
I have Compass 360 Pro on my Android tablet and it gives a reading of magnetic field strength in the centre of the compass dial.