Falsing

[foreign object]

I have several spots that I hunt that are nail beds without peer. The problem is I get constant falsing. Ever swing produces sever false hits.
I've tried every setting change that I can think of with no change.
I am using the 6" coil.

Any help will be appreciated.
Thanks

 

[parkgt]

When you say falsing do you mean that the CTX is constantly reporting the nails? If that is the case it isn't "false".

Or is it just making a lot of random noise? Is it the same with the stock coil?


Ideas:

Dial down the sensitivity even into the minus to see if that clears it up.

Check connections to be sure they are tight.

Look for some form of EMI in the area that noise cancel can't overcome. I have an underground dog fence that the CTX can't handle for instance.

 

[foreign object]

It's not emi. In areas not nail infested it does fine.
It is falsing on the nails. Gives non repeatable high tones.

Thanks

 

[Digger]

try slowing down your sweep speed. That usually takes care of those chirps. And like parkgt suggested, lower the Sensitivity. Auto without an offset is still quite "hot".

You didn't mention your level of discrimination.......if they still bark at you, even with the slower sweep, confirm the TID numbers and reject the notches where they commonly appear. (e.g. 01/50) I'd also suggest Ferrous Coin Separation, and Combined audio. JMHO HH Randy

 

[foreign object]

I tried running auto sen without off set and did not help.

Running Ferrous Coin combined.

I have everything from Fe 24 up disc out and 1-49 / 1-50 Thur 7-50

Will try slowing down my sweep speed and see what happens.

Thanks guys
FO

 

[nolanation]

It's not emi. In areas not nail infested it does fine.
It is falsing on the nails. Gives non repeatable high tones.

Thanks

That's normal. All machines false on iron.

 

[G. E. Edwards]

Change back to your stock coil, if it still does it, a call to Minelab might be needed. I'm thinking there might be more under the ground then just nails, like a vast array of aluminum,coils,copper,tin, that is making the detector go nuts trying to report all that's down there at the same time, just a thought.

 

[foreign object]

It's not emi. In areas not nail infested it does fine.
It is falsing on the nails. Gives non repeatable high tones.

Thanks

That's normal. All machines false on iron.

Yes they do to some extent. I have had used several machines in these same spots and none of them ever gave false signals like I am getting with my CTX.
I plan to change coils today and see what happens.
Thanks guys

 

[Mike MD]

Is the falsing occurring at the end of your swing when you change directions?

I finally got out yesterday after the snow melt and had a lot of falsing, but the ground is saturated. No problem as they were not repeatable. I did manage two silver Rosies.
Mike

 

[foreign object]

Is the falsing occurring at the end of your swing when you change directions?

I finally got out yesterday after the snow melt and had a lot of falsing, but the ground is saturated. No problem as they were not repeatable. I did manage two silver Rosies.
Mike

Yes and no. It will false some times at the end of the swing but the majority of the falses are during the sweep.
The 6" coil is a little light which makes it a bit hard to control as well as i would like so i added some weight to the end of the shaft which helps a lot. And yes the weight is non conductive and the false signals are the same with or without the added weight.

Thanks again guys

 

[Johnnyanglo]

Nails will produce a "high" chirp due to their shape. The pointy tip and round head, or bent corners, will produce a signal that is similar to a conductive target (like a coin). The difference is the coin will repeat the audio with identical sweeps (same sweep angle) and have a sharper audio (or broader audio if deeper) but will be clearly different than the tiny high chirp of a nail.

You have a few choices to hunt nail beds. First, use intelligent discrimination to limit the high tone (disc out the top line of the upper right corner and a few rows of the bottom right). Too much disc will reduce your ability to find conductive targets in fields of iron - it will quiet the nails and make hunting more pleasant, but will also silence any hope of finding that coin in-between nails. Second, nails generally will silence any conductive target if both are under the coil - unless separated by 4-5". A nail swept parallel (lengthwise) will kill all other signals (the machine will go silent over a nearby coin). Your best hope is to hunt with a smaller coil (like the 6"), go very slow, change attack angles (sweep angles), and listen carefully for the fuller coin high tone (not truncated).

If you find a suspect target and you can't get the high tone again - move on. If you at least get a good audio it will probably be along exactly the same sweep path (usually need to change from wide sweeps to small movements of 3-4" or less along a single radial over the suspected target). By changing the sweep radial you are changing the way the nails are illuminated (they are very sensitive to angle of illumination - they only 'chirp' at certain angles). You are trying to find an angle where there is no nail parallel to your sweep (perpendicular nails will mask the coin too, but not to the same degree). If you got a good tone it may still be junk - you want to get enough returns from the target that the machine can give a TID - at least to avoid digging shallow trash. Watch the depth meter - if you can get a low-high-low (you can't see it - but the detector needs to know the max return signal has occurred) the depth meter can give the depth (based on a coin sized target). Otherwise, you'll probably get no depth reading (or an invalid depth). Generally, deeper targets are more likely valuable than shallow targets (surface trash).

Is this tiring to do? Absolutely. Trying to discern a single tone from a chorus of chirps and clicks is mentally tiring. But you can be sure other detectorists have passed these iron fields by for easier soil. It takes practice to get good - but when you can do it you'll find targets others have missed. You'll also be much more accomplished in calmer soil - which will become like child's play.

Johnnanglo

 

[GKMan]

Well said Johnny

 

[foreign object]

Thanks guys. One of the places I am trying to hunt dates back to 1850s and was a bed and breakfast for traveling salesman and the like.It was bought by my wife's dad in 1951 and he raised 9 kids there so you can just imagine the potential. But it is a square nail haven. I feel sure that it has had very little detecting pressure besides me. It is tough.

Once again thanks
FO

 

[GKMan]

Woops, in my last response I meant to put the bowing down emoticon,not the little fiddle dude

 

[Fletch88]

If you can stand the audio (maybe turn volume down quite a bit) try this method. But watch out for those "blubs" . I know he calls his CTX an Etrac but if you look at his other vids it would be quite hard to keep up with which one I had in hand too!
http://youtu.be/MKoYJ2q8Vok

 

[flhunter]

hey you're absolutely right, my detector does the exact same thing. I'll get a choppy 12.45 with a diagonal target trace to the bottom right hand corner. I'll dig it because I'm hoping it's a silver coin with nails in the same hole, I dig the hole and pull out a couple or more nails and get no other signals.

It drives me nuts, but here is my best advice:

run ground-coin not ferrous coin in these spots.
if you can't get a repeatable signal from one angle, then at 90 degree change then most of the time it's a falsing.

I use the stock coil or the 6'' coil, it makes no difference in these situtations.

 

[harryhh]

Maybe I'm missing something here, but I don't see this as 'falsing.' The ctx is my first detector so I don't know how other machines handle rusted iron. But this is what I see with the ctx.

I have Target Trace turned on. With that, you can see all the multiple readings on the screen that you get from rusted iron. Rusted iron will generally produce a scattering of dots on the screen starting in the lower right area of the screen and moving upward and a little to the left. Sometimes all the way to the top of the screen. When they do this, some of the dots go right through my accept pattern on the screen and I get a beep. I don't consider this falsing. It's just how the ctx reads rusted iron.

I pass over the target several times to see if it will build a dot in the good area. I change directions 90 degrees to see if it will build a dot in the good area. If I get nothing that looks good, I pass it up as rusted iron. If in doubt, I dig it.

Sometimes rusted iron will leave a 'halo effect' in the ground. The iron has rusted away, but there is still an iron 'signature' left behind. Often when you dig this, the signal disappears. Disturbing the soil destroys the halo effect.

 

[INSAYN]

FO, you mentioned Square nails.
Square nails in my soil tend to ring off like a coin.
They still are off center during pinpoint, but sound soooo good.
I like square nails, so I dig them.

Since this property sounds like you have unlimited access to, I'd say put down 4 plastic poker chips in a 3'x'3' square.
Turn on your GPS and run Geo hunts over as much of the property as you can stand.
Use your 6" coil and go slow. Dig everything that is repeatable.
After fully covering that 3'x3' square, hit it again from 3 other directions including diagonally.
After you have completely cleared this section of soil, move two of the poker chips forward 3' creating a new patch.
Upload your Geo hunt to the XChange2 program, and put it into a folder you could name 1850 B&B.
Each time you get to work that property you can run another Geo hunt and continue to clear more ground completely.
And each time, upload your Geo hunt to that same folder.
You will be able to see what areas you have covered all at the same time, but additionally can highlight each individual hunt on the map overlay as well.
If you are finding great stuff, pop a Findpoint right then and there and later you can edit what it was in XChange2, and even add a picture of it.

Sounds like you have an awesome problem to work through.
I wish it were my problem.
Good luck and keep us posted on your progress.

 

[sube]

Just a point about nails older nails were not as refined as newer nails square nails have a higher concentration of non-ferrous metals in them than newer nails . Some of the iron had copper nickel zinc and other metals mixed with them . As the nail rust away the nonferrous metals become more concentrated leaving it more likely to sound off as a good hit . Nonferrous metals do not decompose as fast as iron the only way to see what is in the square nail is to have it analyzed . Square nails have different non ferrous metal in them depending where they were made . That said good luck . sube