Any metal detector experts here?

[brandon7861]

I know its not really radio related, but it does transmit and receive

On our little lake, there are some very good stories from days past. One of them was about the farmers wife who got mad and tossed his still in the lake. We figure within throwing distance of a strong farm woman, it is probably no deeper than 25'. The neighbors kid wants to find the still and I thought it would be fun to try to build a metal detector that can be pulled across the lake this winter (and right now we have nice clear ice and very little snow... )

I know this is an impossible depth for typical handheld beach detectors, but I figured on making a 1 meter wide coil and running it on a homemade driver and monitoring the response with the laptop and oscilloscope in persistence mode.

Being it is a larger target, the large coil size should not exclude the still. But what method do I use? Pulse induction, Double D, or will I need to go with two separate coils to get that deep? This is fresh water, but the area is highly mineralized and the bottom is clay. Any advice out there? Thanks!

 

[Shadetree Mechanic]

Maybe you could modify a metal detector and put an amplifier on it? Then make a giant coil with the same impedance? The magnetic fields would need to be fairly large to go under water that far. Maybe in the spring, you could put a waterproof detector head on a pole and sweep the bottom? I am interested to see what you come up with.

 

[brandon7861]

Maybe you could modify a metal detector and put an amplifier on it? Then make a giant coil with the same impedance? The magnetic fields would need to be fairly large to go under water that far. Maybe in the spring, you could put a waterproof detector head on a pole and sweep the bottom? I am interested to see what you come up with.

I was hoping to avoid going underwater as the area in question has trees everywhere and the beaver have made a hut and filled the bottom with branches where the stories say I need to look. Sweeping under water would be a real challenge.

 

[Shadetree Mechanic]

Maybe a small boat with a fish finder?

Home brew LiDAR?

Redirect Notice

www.google.com

Maybe GPR Ground penetrating radar?

 

[brandon7861]

Maybe a small boat with a fish finder?

Home brew LiDAR?

Redirect Notice

www.google.com

Maybe GPR Ground penetrating radar?

Not sure lidar would work with all the branches and weeds. GPR would be well outside my ambition level too.

I will save that pdf, very good info! thanks!