sensitivity and ground balance problems on man-made beaches

[log2lumber]

So I am having trouble on some man made beaches on lakes in parks. No matter what I do even after ground balancing, I get a lot of feedback and false signals.
Most of the false signal say the target is 6 to 10" deep. I dig a crater, check the crater and sand and nothing shows. After digging about 4 to 6", the ground is either silt or very black dirt which is generally wet, even when detecting the dry part of the beaches.

The depth reading is never accurate.

I am running my at pro in pro-coin, iron discrimination 37, and I ground balance a couple of times. Sensitive is 2 bars down.

Any ideas?

 

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[The Aluminum Monster]

I imagine if you dig a few more inches (or feet!) down, you're going to find a whole lot of wet hot rocks, more than likely from the same source quarry, holding all that beach sand in place. Would I be correct in assuming all your readings are coming in the high 90s? 99?

 

[Pennypacker]

That's the way she goes when she goes.

You can try turning down your sensitivity even more until the detector calms down, you will technically lose some depth, but you may make it up in functionality.

It is a common challenge for most detectors. You can get around it by using a pulse induction detector, or a multi-frequency induction balance detector if you want discrimination.
Right now you have a single frequency induction balance, like most detectors.

I wouldn't worry about the depth gauge too much, most are reasonably accurate at times when detecting coin sized objects that are reasonably shallow. (When they are least needed lol)

As the Aluminum Monster mentioned, it could be deep or abundant mineralization or even a deep pop can.

Try another beach or stick to the green. You might even check back at a later date, the conditions might be a slightly better.

 

[redcobra8u]

I run mine almost the same as you. Do you live in an area where there is salt? Either mined or the sand was brought in from salt water areas? It could be hot rocks or power lines too but what you describe sounds like a salty sand problem. Does it make the same sound in the water?

 

[WaterWalker]

Some fresh water beaches I have detected have weed control mats below the "sand". The mats are anchored down, some with stainless steel rods. others have PVC at the edges and they are anchored down. At any rate if you dig far enough, you can destroy the mats. In doing so detecting may be outlawed. I know of one private camp that no longer lets detectorist in...BE CAREFUL - PLEASE.

One beach in SW Massachusetts uses stainless steel "cork-screws" that one would never be able to dig up with a scoop. I talked to the installers, learned about the great product which is almost indestructible, but a scoop with a point could penetrate the fabric.

Another beach has a concrete "slab" with re-bar in it hidden under the sand bottom. Good luck detecting this beach.

I may be wrong here, but I believe the depth reading on most detectors is set for a coin sized object, a gallon can down 2 feet might read as a coin at 6 or 8 inches.

 

[dewcon4414]

Mineral concentration, deep iron, and shallow hot rocks, or salt can do this. Normally because of to much sensitivity which causes wrap around...... or iron to swing to the positive side. Can also be bad coil control where you are lifting your coil at the end of your swing. Try using AM once that signal disappears ..... in and out of the hole, you might just find the target and have your answer.

Dew

 

[log2lumber]

@Aluminum Monster - readings vary. A lot in the 53 and 81 range with nothing there.

 

[log2lumber]

@redcobra 8u - it does not make the same sound in the water, especially the river which the bottom is too hard to dig more than a couple of inches. This is freshwater, not salt.

 

[log2lumber]

@Walterwalker - all three beaches do not have fabric

 

[Professor of Engineering]

Hello log2lumber,

The +/-53 is a nickel reading and the +/-81 is a cent or dime reading for me in soil and sand. Strange that both of these signals would produce no targets for you. Have you practiced pin pointing (water and soil) objects? Have you made a test bed in your yard? The AT pro is equipped with a DD coil and does require a bit of practice to accurately locate a target; Just thinking out loud. I hope you can resolve the issue, there may be goodies waiting in the area.

Regards,

 

[redcobra8u]

You might have an issue the needs servicing

 

[log2lumber]

Thanks everyone,
watched a youtube video on the subject...set the detector for pro/all metal/iron 38, then found a spot to ground balance.
used the detector with iron audio on and only hit clear sounds. Found about 4x as much stuff as running pro/coin mode/iron 37.

only had 2 holes with false signals even with pin pointer could not find. My guess is hot rocks since i have pulled rocks out that were the signal.