Detector Recommendation For Gold Coins Under Floor

[aregb]

Many years ago, we found various gold chains hidden by my great grand grandfather in one of our apartments. My parents also remember various gold coins that were never accounted for, and the time has finally come to do a proper search in the old apartment.

I have spent hours reading, but I find its quite hard to understand what kind of equipment we actually need.

So basically, I need recommendations for gold detectors that covers these criteria:

- Max search depth <10 inches, I believe the floor is around 5-7 inches deep.

- Floor consists of some layers of wood, an air gap, and dirt. Under the dirt, there is concrete with no interest to us.

- Needs to properly discriminate between ferrous and non-ferrous metals.

-  Except for iron nails and the gold coins were looking for, there is a very low chance of metals in the floor.

 

We have no other interest in using the detector after this adventure, so we will probably sell it off for cheap. Ergo, no need for a super advanced deluxe detector if not strictly required. But we will happily pay what is necessary to avoid dismantling the whole floor.

 

[phrunt]

Unless you cut power to the place EMI is going to be an issue with many detectors.   I would think this wouldn't be that much of a challenge for any detector though to meet your needs aside from EMI,  I wonder if the concrete has reinforcing bar in it, if so you're in trouble.   

Something like the new X-Terra Pro would do it fine for minimal cost and has different frequencies you can switch into to help mitigate EMI.  15kHz should do the job nicely for gold coins and EMI handling, if not 10kHz.  It's handy because you can switch frequencies on it.  

[aregb]

Thanks for the tip. I believe that there is no electric wires in the floor itself, although probably plenty usage of reinforcing bars as it's fourth floor. Are electric wires in the walls going to cause EMI issues? 

[aregb]

For the X-Terra Pro, would the default search coil be sufficient, or would we gain anything from purchasing a different one?

[phrunt]

The EMI comes from the power, not so much from the wires themselves, but the power going through them and anything people have plugged into that power like wireless routers, fridges, fluro or LED lights etc, everything emits EMI that becomes a challenge for a detector.  High density living areas are bad for EMI sources.

The reinforcing bar will likely overload the detector with a signal so if the target was right near the bar its unlikely you will find the target so in this case a smaller coil might be better than the standard coil, for better target separation along with better EMI handling with a small coil.    The side effect of the small coil is less depth although it doesn't sound like the coins would be at a depth anyway,  You could try the larger coil first, and if no luck invest in the 6" coil.

[aregb]

I understand the physics behind EMI, my thinking was that it would mostly be an issue close to the wires as that's where its going to be strongest. But while I have worked with systems where EMI can disturb the results, I have no experience with metal detectors, so I appreciate the input.
As we dont live in the same country as the apartment (8 hours total flight time one way), we will have to purchase all the equipment beforehand, but getting the extra coil is not really going to break the bank, even if we find out it was unnecessary. Rather have more equipment than we need, than get there and end up missing something.

From what I can gather, the X-Terra seems like a capable machine, would you say its worth reading up on alternatives?

[phrunt]

The Legend would be another excellent option without breaking the bank, and has even more frequency options to choose from along with Multi Frequency's at once although in a high EMI area you'd probably be better off in single frequencies.  Detectors pick up EMI from quite a distance, using them indoors inside a house can be a challenge and even more so in an apartment building with multiple residences.   The closer you are to the source the worse it is obviously however to a detector 100 meters (300+ feet) is considered close to a power line.  Some detectors run better than others usually based upon the frequency they're in being away from the EMI's frequency which is why these switching single frequency detectors can often handle EMI the best as you can use a frequency away from the EMI sources frequency.  The more sources of EMI the more difficult that becomes. 

Here I find 19kHz detectors work best inside my house with the local sources of EMI, so the Legend having 20kHz would work perfectly well indoors here. 

So it's worth looking into and researching the Legend also, it has an array of coil options including a small coil, the smaller the coil the less affected by EMI it is, but the smaller coils have less depth than the bigger coils.  In saying that as contradictory as it may sound a big coil being troubled by EMI will end up with less depth than a smaller coil that is less affected by the EMI. 

It's complicated 🙂

[aregb]

Thanks for all the good input. As everything else in life, it seems like a good compromise needs to be found 🙂

[Old Miner Don]

Wish you could describe the floor better. 4th floor apartment would have a poured concrete floor I suppose. Like a high rise. Why is there dirt on top of that concrete and how deep is the dirt? Sounds like that's probably where the coins will be hidden is in the dirt. 

And the boards above the dirt will have nails holding them down won't they? Which means the detector will be sounding off on the nails. How big is the gap between the bottom of the boards and the top of the dirt?

When I read your question I was thinking that you need a crowbar AND a detector. You obviously will have to remove some wood flooring to recover anything buried in the dirt. After you locate it of course. It's just a bare wood floor correct? Check out the floor very carefully and you just might be able to find the wood that grandpa removed many years ago.

Good luck and please let us know what happens!

[kac]

Wood floors will have nails or staples which will make detecting tough. Any copper pipes or cast iron pipes will also be a problem.

Just about any of the modern detectors will detect the depth you need but getting past the nails, wires and pipes can be a pain.

Concrete may have rebar depending on age of the house.