When your pinpointer detects grass from 8 inches up...

davemill

Junior Member
Joined
Nov 10, 2008
Messages
81
Location
Santa Cruz, CA
Yesterday I was asked to find a ring lost by a woman during a football game in the grass at the San Francisco Presidio. Two people saw it fly off, so it should have been a slam dunk. This is where she was standing:

1425317346770


Fail #1: DFX with Bigfoot coil failed to ground balance, and chattered badly everywhere I tried to search over a 50-foot radius. No visible power lines.

Fail #2: AT-Pro failed to ground balance, chattered madly, and I could not notch out the problem. Hmmm....

Fail #3: Garrett ProPointer detected the grass from 8 inches/20cm everywhere. Here's the video:


Anyone know what's going on here? No matter where I went in the big grassy area, the pinpointer still detected the grass from 8 inches. I've detected over buried pipes, power lines, steel plates and fuel tanks, but never seen a situation like this. My guess is that there's a big UFO buried under the whole base. Or a more mundane explanation would be a steel plate or chain link fence a few inches down. Unfortunately for the curious, digging was not an option.

By the way, Fail #4: We searched on hands and knees for an hour until the light was gone. They gave up, but promised they would post on Craigslist.

Here's the YouTube link again if it doesn't work above:
http://www.youtube.com/watch?v=0rzePxFNqr8

Here's where she was standing. The ring is likely in the quadrant to the north and west of this point. If anyone were to find it, I could connect you with them and they would likely pay a nice reward.
https://www.google.com/maps/place/3...2.4576417,90m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0
 
Would have been one very large, flat, metallic sewer line...the signal was uniform across the entire grassy area.
 
That's wild! All of your equipment can't be wrong. Buried nuclear submarine?
Government security system? It would be tough to descriminate out whatever is causing that. Sad that you can't help her.
 
Would have been one very large, flat, metallic sewer line...the signal was uniform across the entire grassy area.

If they were gridded they may cover that entire grass area.

Maybe there were fiber optic lines underground...

Have you seen historic photos of that area? Maybe there was a parking lot or something that had rebar through it and was later covered with topsoil and sod?

The wire mesh we would roll out when doing concrete for reinforcement would do that if you went over parking lots, sidewalks, house floors, with a pinpointer

Maybe there is an irrigation system underground etc
 
I think I know what you're problem is. A buddy of mine encountered it when he tried to detect on the presidio there too. He'd met a gal who actually lived in one of the turn-of-the-century homes there (the old base housing). And had gotten permission to hunt the yard.

He showed up on the appointed day, and got to work detecting the yard. And immediately it was just as you say: static, falsing, beeps, etc... everywhere. Finally he got a signal, he thought, to repeat enough in one spot. He stopped down to dig. At a few inches down, he encountered the culprit: CHICKEN SCREEN ! Yup, they apparently put that stuff down under various turfed surfaces at the presidio there, in an attempt at gopher control. He gave up and left.

So it could be that the football field you speak of, has the same thing. To determine this, just have your connection on site there (like if the woman lives close ), to go there with a garden trowel. Have her cut a sample plug (with a catch mat of some sort ready). And do a sample few handfulls (10 or 12" deep) test spot. Uh .... discreetly, of course, so no one gets their panties in a wad. If she hits that metal chicken screen stuff, that'll answer your question right there.
 
If it is indeed that Chicken screen stuff, there is still some md'ing methods that can overcome it. First find out if that's the case, and also find out how deep they've laid it. Then come back on the thread to report. I know of a machine and a setup that can get coin & rings despite that, presuming they're above the mesh. And, of course, the ring being on top, would be above the screen. doh!

Our normal power house deep-seekers are going to mask and such. But there's old school all-metal TRs that ....... although not deep, and although not able to discern TID's, can indeed get a threshold hum, and only find find targets above said-layer. What is the amt. of the reward being offered ?
 
could you reduce to a low sensitivity at all since you were looking for a surface find? If not, maybe there is a large communications tower close bye.
 
I would reduce the sensitivity all the way down on my ATP. I have used this approach before. Then if you still can't GB, take a guess at what it is and go from there. I would also discriminate up to 30 or 35.
 
Maybe this has been suggested...why not dig a deep hole and see what's down there? I did that once here in my yard and it was indeed chicken wire. Second deep dig was my septic tank. I would definitely run my detector at near zero gain. The PPR seeing something at 8 inches in air tells me you likely have very large.

Just dig. It's shovel time.
 
Re: Chicken Wire:
I've encountered this before. You can raise your coil and, if the chicken wire is buried far enough under the surface, still detect items in the grass, which is where a ring lost that day would be. In this case, as the video shows, no detecting at all was possible. I couldn't detect my keys placed on the surface.

Re: Antennas, septic tanks, power lines:
The interference was quite uniform, and quite clearly underground. As you can see in the video, my pinpointer beeped 8 inches above the ground. This was a uniform response across the entire field, with no noticeable variations.

If you imagine the signal you'd get from a steel street plate buried about 2 inches down, that's what I got.

Re: Digging:
This is a very public location with a very nicely manicured lawn, on the day of a big event. I elected not to dig. Perhaps that was an error.

Thanks for all the answers. I sent them Tom_in_CA's contact info, they said they will contact him.
 
Yesterday I was asked to find a ring lost by a woman during a football game in the grass at the San Francisco Presidio. Two people saw it fly off, so it should have been a slam dunk. This is where she was standing:

1425317346770


Fail #1: DFX with Bigfoot coil failed to ground balance, and chattered badly everywhere I tried to search over a 50-foot radius. No visible power lines.

Fail #2: AT-Pro failed to ground balance, chattered madly, and I could not notch out the problem. Hmmm....

Fail #3: Garrett ProPointer detected the grass from 8 inches/20cm everywhere. Here's the video:


Anyone know what's going on here? No matter where I went in the big grassy area, the pinpointer still detected the grass from 8 inches. I've detected over buried pipes, power lines, steel plates and fuel tanks, but never seen a situation like this. My guess is that there's a big UFO buried under the whole base. Or a more mundane explanation would be a steel plate or chain link fence a few inches down. Unfortunately for the curious, digging was not an option.

By the way, Fail #4: We searched on hands and knees for an hour until the light was gone. They gave up, but promised they would post on Craigslist.

Here's the YouTube link again if it doesn't work above:
http://www.youtube.com/watch?v=0rzePxFNqr8

Here's where she was standing. The ring is likely in the quadrant to the north and west of this point. If anyone were to find it, I could connect you with them and they would likely pay a nice reward.
https://www.google.com/maps/place/3...2.4576417,90m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0

if u know of 2 people that seen it fly off...sounds to me there was a 3rd person who seen it fly also....then stuck it in their pocket!
 
It happened again!

So 30 months later it happened again. I'm at a rugby field to recover a lost ring, but can't get my DFX to ground balance. I switch coils, lower the sensitivity, nothing works. Then I tried pinpointing the ground...yup. Everywhere on the field, the pinpointer started beeping 6+ inches above the ground.

Here's the culprit:
https://gopherslimited.com/wire-roll-installation/

Just looking at those pictures makes me groan.
 
Pulltabs, rusty nails,beer caps,athelic shoe spikes, eraser heads, crack head glue tubes, junkie needles, zipper pulls,foil wrap, now chicken wire uggggg:lol:
 
I've got a couple of fields that do that locally, as long as the electrical grid is on. Something about the electromagnetic fields around whatever is below the surface (I think tied to irrigation lines, somehow...) I actually have NO idea what actually causes it, only that the noise level is INSANE until they turn it off briefly for a few weeks in the winter.

That being said, it IS huntable, if you're willing to deal with the chatter.

First step is to find the frequency on the AT Pro which has the LEAST chatter. It'll be one of them. That's the easy part.

Step two is to lower your sensitivity to just one or two notches. This will help but will not REMOVE the chatter.

Third step is to throw a ring on the ground, and wave your coil over it. You'll notice immediately that the chatter actually gets INTERRUPTED by the strong repeatable signal. And THAT is what you're looking for. That repeatable signal in between the chatter.

I've found no less than 4 gold rings in nasty chatter, one this year, that was worth over $3K with nice diamonds. The key is listening for the interrupt.

Now, here's where it gets nasty. With all that chatter, and the location, the field will no doubt be filled with all kinds of garbage... you'll have to clear it in the section you're searching... But you'll find stuff!

I wish I was there to help you out. I gotta say, it CAN be done. It really can! Just check out a signal interrupt with a real item.

Once i figured that out, I stopped worrying about chattery places. You can detect just fine, if you learn to hear the repeatable signals (it usually means, though, two sweeps through every area). I find plenty of rings below powerlines in parks, this way.

Cheers,

Skippy
 
I've got a couple of fields that do that locally, as long as the electrical grid is on. Something about the electromagnetic fields around whatever is below the surface (I think tied to irrigation lines, somehow...) I actually have NO idea what actually causes it, only that the noise level is INSANE until they turn it off briefly for a few weeks in the winter.

That being said, it IS huntable, if you're willing to deal with the chatter.

First step is to find the frequency on the AT Pro which has the LEAST chatter. It'll be one of them. That's the easy part.

Step two is to lower your sensitivity to just one or two notches. This will help but will not REMOVE the chatter.

Third step is to throw a ring on the ground, and wave your coil over it. You'll notice immediately that the chatter actually gets INTERRUPTED by the strong repeatable signal. And THAT is what you're looking for. That repeatable signal in between the chatter.

I've found no less than 4 gold rings in nasty chatter, one this year, that was worth over $3K with nice diamonds. The key is listening for the interrupt.

Now, here's where it gets nasty. With all that chatter, and the location, the field will no doubt be filled with all kinds of garbage... you'll have to clear it in the section you're searching... But you'll find stuff!

I wish I was there to help you out. I gotta say, it CAN be done. It really can! Just check out a signal interrupt with a real item.

Once i figured that out, I stopped worrying about chattery places. You can detect just fine, if you learn to hear the repeatable signals (it usually means, though, two sweeps through every area). I find plenty of rings below powerlines in parks, this way.

Cheers,

Skippy

interesting post.

Use the PINPOINT/Freq Adj push button in conjunction with the (+) or (-) SENSITIVITY push buttons to adjust frequency.The AT Pro is capable of operating at four slightly different frequencies in order to minimize the interference caused by electrical sources (e.g. power lines) or other metal detectors.To adjust frequencies, hold down the PINPOINT button and press the (+) or (-) SENSITIVITy push buttons to change the frequency to find one with the least amount of interference.The frequency setting (F1–F4) will be indicated on the LCD.Release the PINPOINT button when finished.Note: Frequency adjustments are small and therefore do not affect target detection capabilities.
 
I would think also, that even with gopher wire, the chatter would be doable for finding repeatable signals. No different than dealing with chatter in black sands at a beach. The key is to find something NON-random...

Skippy
 
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