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Question about sand detecting

Colt0208

New Member
Joined
Aug 4, 2021
Messages
9
Location
Hockessin, DE
So I am a complete newb to detecting.... The other day we were searching a small beach on the river where there used to be a dock in the late 1800's... I kept getting what I thought was a good signal, but after digging discovered there was water below the surface of the sand...

So my question is, can water under the surface of the sand give a false signal? I only noticed it happening in this area closer to the river. The dry sand up further didn't produce this...

I am running a Garrett AT Pro on the "Pro Coin" factory setting
 
Does that river flow into an estuary? It's possible where you hunted had some brackish water? If so, that might explain the false signal.

Another possibility is that the water "enhanced" the mineralization or potential targets below the surface. From personal experience, I know that damp or wet soil will add a few VDI points to some targets. And in clay (where I'm at), adding water can give a false signal. For example, with a Vanquish in soil after a rain in my back yard, it will give VDIs in the uppers 20s and lower 30s, which is equivalent to lower 80s (give or take) on my AT Max. Yet when you dig, all you get is sopping wet clay.

Are you ground balancing before you hunt in that area? And if so, how deep did you dig to get to that "good" signal where all you found was water?
 
I see you are using an AT Pro. Being a single-frequency detector, it won't do well at saltwater beaches due to the mineralization/salt...it will be chatty and can give false signals.
 
Does that river flow into an estuary? It's possible where you hunted had some brackish water? If so, that might explain the false signal.

Another possibility is that the water "enhanced" the mineralization or potential targets below the surface. From personal experience, I know that damp or wet soil will add a few VDI points to some targets. And in clay (where I'm at), adding water can give a false signal. For example, with a Vanquish in soil after a rain in my back yard, it will give VDIs in the uppers 20s and lower 30s, which is equivalent to lower 80s (give or take) on my AT Max. Yet when you dig, all you get is sopping wet clay.

Are you ground balancing before you hunt in that area? And if so, how deep did you dig to get to that "good" signal where all you found was water?

It is a brackish river.... I dug out a pretty good sized area about a foot down and the hole would fill with water.... I have scoop and nothing in there, the signal would still be there in the hole... And yes, I ground balanced for the wet sand and then again for the dry sand up on the beach further....
 
I see you are using an AT Pro. Being a single-frequency detector, it won't do well at saltwater beaches due to the mineralization/salt...it will be chatty and can give false signals.

River water in his case, not salt. About single VLF machines in salt water...the Whites M6 was great at salt water beaches. jm2c

To be clear. The M6 did require the concentric, not DD coil at saltwater beaches. I never tried a DD coil there. Do the multi frequency machines do well at salt beaches and wet sand, using DD coils. Thanks. Was the AT Pro using a concentric and still getting this chatter?
 
River water in his case, not salt. About single VLF machines in salt water...the Whites M6 was great at salt water beaches. jm2c

To be clear. The M6 did require the concentric, not DD coil at saltwater beaches. I never tried a DD coil there. Do the multi frequency machines do well at salt beaches and wet sand, using DD coils. Thanks. Was the AT Pro using a concentric and still getting this chatter?

It's a DD coil.....
 
It is a brackish river.... I dug out a pretty good sized area about a foot down and the hole would fill with water.... I have scoop and nothing in there, the signal would still be there in the hole... And yes, I ground balanced for the wet sand and then again for the dry sand up on the beach further....

I don't have any river hunting experience, but I wonder if you're digging in highly mineralized soil that soaked with salt (brackish) water. If so, that could explain your false signals.

To handle these conditions you generally want a machine that has simultaneous multifrequency with ground balancing capability OR a pulse induction machine. The AT Pro is neither.
 
Does it still do the same when you wander further up and down stream? You might possibly have something big in the one spot.
 
Does it still do the same when you wander further up and down stream? You might possibly have something big in the one spot.


Yeah, its the same down by the water line..... the water table is really high there, so anything more than a few inches down fills with brackish water pretty quickly.... If I'm up in the dry sand further up the little beach area, I don't have that going on at all.... only actual hits ring....
 
He said it's brackish...not fresh...so yes, saltwater and it will affect it.

I'm thinking its the little bit of salt in the water that's doing it. The water table is super high there, so even on the bank, if you dig a few inches down it will fill the hole with water pretty quickly......
 
I'm thinking its the little bit of salt in the water that's doing it. The water table is super high there, so even on the bank, if you dig a few inches down it will fill the hole with water pretty quickly......

You can try lowering the sensitivity a notch at a time until the falsing stops.
 
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