Pinpointing Accuracy? Not so much.. :rage:

[Mezrein]

Ok, Ive begun to notice something, not sure if its always been like this or if its something new, but when pinpointing now and again I'll sweep a solid hitting target, I'll x it out, just like everyone says to do, then I'll hit my pinpoint on the F5 get to the strongest sound, and I'll dig. And dig. And dig...... by the time my digger is showing 5" and my hand held pinpointer isnt finding anything, and my F5 pinpoint said the target was 2" down, Im starting to wonder. So I tear apart the plug. Nothing... Ok... Maybe it was a false signal... replace whats left of the plug, grab the detector, sweep the spot, nothing, sweep to the right about 2" and theres the signal again....... But when I X, nothing, when I pinpoint, nothing, when I pinpoint where I just was, hey its back, but my coil is no where near where I just suddenly had that loud signal, and I know there's nothing in this hole to a depth of 8"

So.... what the crap... Is this happening because of how concentric coils project a cone of detection underneath them? Will a DD fix this? I have a very finite amount of time to detect, due to weather and the fact that I can only go in the mornings before work, and sometimes rarely on weekends. So I dont need to be wasting my time digging for targets that are actually 3 inches away from where my pinpointer said they were..

I promise I'm not whining, I just want my detector to be accurate, at least, more so than this. I expect when I pinpoint that the strongest sound is directly in front of the rod, and when I dig my plug around that, that the target is somewhere beneath the coil.

 

[crusher28]

I have the same problem on the beach. little earring studs that fall threw the sand scoop can drive you crazy can"t See them have to feel around for them

 

[Dave J.]

If you're not properly ground balanced it can really mess up your pinpointing, and can also cause you to believe something's there when there's not.

Also if you're working in an area where there are mineral salts from fertilizer, livestock urine, de-icing salts, etc., wet spots will sound off but when you dig them you break up the electrical conductivity and they disappear.

--Dave J.

 

[TerraDigger]

Why not just bury a dime to 5" and see how the machine handles it. If it works fine, the perhaps you may want to consider what Dave J. has outlined.

 

[Big Boys Hobbies]

Sure its not a deep smashed up beer can? Swing the coil several inches above the ground. A coin will fade away if its there. Beer can wont.

 

[hershey1]

Put a target on top of the ground that you can see and practice on it. Make sure you swing your coil a little to the side of the target engage PP and locate it. Once you get that PP down holes get smaller and smiles get wider. Good luck. Come on Dave a new guy or gal don't need to hear about cow urine.

 

[hershey1]

Put a target on top of the ground that you can see and practice on it. Make sure you swing your coil a little to the side of the target engage PP and locate it. Once you get that PP down holes get smaller and smiles get wider. Good luck. Come on Dave a new guy or gal don't need to hear about cow urine.

 

[WV62]

If you're not properly ground balanced it can really mess up your pinpointing, and can also cause you to believe something's there when there's not.

Also if you're working in an area where there are mineral salts from fertilizer, livestock urine, de-icing salts, etc., wet spots will sound off but when you dig them you break up the electrical conductivity and they disappear.

--Dave J.

Dave J. This little bit of information answers a lot of questions for me. Thanks Ron in WV

 

[Mezrein]

Sorry for delays in responding, but to answer a few questions.

Ya I'm sure I was properally GB'ed, I GB anytime my fe meter changes in drastic ways, i.e, inital gb at 50, then I swing into an area were I'm getting 25, I'll re GB at that point. Anything more than a 50% difference in the numbers and I'll re ground. The area is a park, so I "guess" it could be dog urine, but they dont manage the ground at all. Its natural soil with original grass to the park. The only thing they do is the at the end of summer, right around this time of month, they aerate they ground. It does have a sprinkler system, but I have the heads marked on a map I drew of the park field, as well as plotted out most likely runs for the pipes supplying those sprinklers, and I wasnt near any of them. Can slaw is possible I guess, the ground was moist, not too wet, not too dry, just right for easy diggin and target recovery. I'll try doing the 5" coin bury, cant do surface, makes the detector go crazy.


P.S
hearing about cow urine doesnt bother, my aunt and uncle use to live on a farm and I helped do chores, milk goats, feed cows and chickens, etc etc.

 

[CarolinaClyde]

That way I can see if the VDI is giving me about the same reading both ways. If id reads about the same both ways, then I'm fairly confident that it's a worthy signal and dig where the signals matched the best in the X. I rarely use the pinpoint trigger due to being a time saver and X-ing the target seems to work good to me. As Dave mentions ground balancing is very important. I will by habit ground balance about every 15 minutes as the ground where I hunt can change very fast.

 

[NE Digger]

I hunt a lot of farm fields.and rerely have problems with urine or little pockets of mineralization unless I'm hunting in All Metal or 0 disc. I'm more inclined to think he has a tiny target and he is just moving it around an missing it. Shallow surface targets will pinpoint waaay off if your scrubbing the coil. I'd just raise the coil a bit, detune, and find the exact center of the signal. OR..........detune and use the tip of the coil.

 

[Occupant]

Another possibility for pinpointing to be off by a few inches is the orientation of the target in the ground. This site (see below) gives a great explanation and graphic to illustrate the problem. If you don't have any problems when testing a coin flat on the ground, try with the target buried at an angle like in the illustration and see what happens.
HH,
Roger in VA

http://metaldetectingworld.com/pinpointing_angled_coins.shtml