Digging Negative Tid Targets

[nordic]

Hey everyone,

Just curious, has anyone tried lowering the tone break T1 to negative numbers or all the way down to -9 on your hunts? Is it worth it, did anything good come out? Or is it just a recipe for headache?

Reason being, I was playing yesterday with the coil and found an old button that is clearly non-ferrous, but gives negative TID in multi-frequency and positive/negative on some single freqs.

Thank you

[67GTA]

Never tried digging negative numbers. They are usually nails or rusty chunks. If you use the old FE setting of zero, the bigger iron pieces will ring up between 13-19. I've had weird readings with iron backed buttons. What kind of button is it?

[Steve Herschbach]

It’s standard practice when nugget detecting because very weak non-ferrous signals in highly iron mineralized ground can tip to ferrous. The ground overwhelms the signal. This does not mean just tiny targets but even large targets like coins right at the edge of detection depth in highly mineralized ground. 

[nordic]

Thanks for replies. I forgot to say, I was air testing it. It is an old copper button about 10mm in diameter, pretty thin, with 4 holes, but due to age, all 4 holes merged together forming a big hole, I'll snap a picture of it when I have a chance. It was giving -1 on 6" coil. There were no other objects beside it, so got me thinking. It reminds me reading somewhere about a stacked coin situation which was giving negative TID as well. FE was 0. Anyway, it is not a big deal really, I did dig it out before somehow!

[midalake]

On 1/7/2020 at 9:20 AM, nordic said:

Hey everyone,

Just curious, has anyone tried lowering the tone break T1 to negative numbers or all the way down to -9 on your hunts? Is it worth it, did anything good come out? Or is it just a recipe for headache?

Reason being, I was playing yesterday with the coil and found an old button that is clearly non-ferrous, but gives negative TID in multi-frequency and positive/negative on some single freqs.

Thank you

I have not put my machine into negative numbers but I have done 100's of digs on iffy beach signals. Where I detect Mexican Peso coins ring -4to-7. Due to mineralization position in the sand and other factors these want to break the threshold.

So lets say I get a breaking sound signal it reads -1 then+2 then -4 then +3. I go in multiple directions then dig. To date with 100's of digs I have yet to dig anything of value.

My point is two fold. First these are clearly targets that are NOT masked. Second there is a strong correlation that when you are given a target that won't lock but "wants" to ring up it is most likely ferrous.   I will say if you are grouping meter numbers most read as a negative with a few low plus number in the swing. 

If you get the reverse and you grouping of meter numbers are positive then it is most likely a keeper.

How many swings?  I would say three back and fourths from TWO different positions should give the information you need.

Dave 

[nordic]

Thanks. The fact that I have dug this button out, it should have indicated positive, I'm just not sure why it is giving me negative swinging it in air. I'm not wearing anything on me that would foul it.

But all who replied, it really coincides with my findings as well, swings from all angles before deciding to dig or not.

If I may extend this thread as well, if anyone has found meteorites, how do they id on the equinox, negative?

[Steve Herschbach]

What is your iron bias setting?

[nordic]

Steve, never really other than 0.

[Steve Herschbach]

Ok, just checking as iron bias would have an effect on that.

[Joe D.]

Hey Nordic,

I'd have to go back and check, but i think Simon has dug multiple stacked coins at cointopia, and i don't think he got negative numbers with the Nox for those! I wonder if the coin nationality/ metal makeup  makes a difference! 

  I've dug some very low +1- +5, but have not found anything good yet! I haven't dug any negative numbers, but i may try just for fun!👍👍