Help needed: distinguishing iron wraparound vs adjacent iron

[samandnoah]

The subject pretty much says it all. When I am hunting, I often find myself slowing down and spending a huge amount of time with non-surface signals that give partial signals, or 1 way, or broken, or bouncy, etc. I typically hunt in 12 kHz and check signals with 4 kHz. With all of the recent postings about using 4 kHz, I did some hunting focused on 4 kHz this past weekend. Things I do to try to resolve the signal:
* Lower or raise reactivity (I almost always keep silencer at 0)
* Use low levels of iron audio to hear any background buzz
* Use Non Motion Audio Disc pinpointing to hear separate targets or determine target size
* Increase or decrease swing speed (depending on reactivity setting, or change in setting) to see if I hear 2 separate targets or just 1
* These are pretty trashy parks, and often need to remove a pull tab or other junk to reduce the number of objects under the coil.

Even after all that, I often do not feel like I can draw a conclusion as to whether I'm getting some deep iron wraparound that sounds good when swung over "just right" vs hearing a non-ferrous target adjacent to iron. One obvious answer is "dig it all". Well, I'm hunting in some parks where that is not really a viable answer; I really need to pick my battles. In places where I can dig more freely, I've ended up with sometimes pulling out just ferrous junk and more rarely a good, non-ferrous target. I haven't always been able to find the iron object affecting the good target. One issue for me is that the good targets have been few and far between, so I haven't had many "wins" for my ears/brain to say "Ahh, that was a good target, and those other ones were junk". I hope that makes sense.

The net is, I feel like I've tried to be pretty methodical about this, but don't feel like I've "learned" anything yet that helps me on a consistent basis. And I think I work too hard at making bad targets sound good, and waste time. So...

Can you guys share what you hear/perceive as the differences?
What other techniques do you use?
Patterns in how the VDI changes (low to high, or high to low) that are indicative?

Thanks!
Rich

 

[Sleepyjim]

I was always told dig all repeatable signals. 1 ways that I did dig are junk....so far. My 1 ways are a gut call for me now as I get in my head and that is not good...LOL

Not much help I know.....


Jim

 

[CZconnoisseur]

After I switched to 4 kHz (sounds like a TV commercial I know LOL), iron has become less of a problem. Today I dug a few iron relics and some Memorials at 7-8" deep, but the relics were circular in shape which will enhance the field conductivity and sometimes make it sound like a coin. Not sure if this helps or if it's in my head, but turning up the "OVERLOAD" to 2 makes large surface targets sound terrible but I think it also helps when IDing deeper iron targets.

VDI is nearly useless for iron objects - I wouldn't rely on it at all if you get a suspect signal. I've dug good-sounding targets that registered LOWER on the VDI than expected; just recently I dug a Jefferson nickel which came in at "72" in 4 kHz - kept looking for the adjacent penny but there wasn't one, and when I scanned the Jefferson by itself it came in at 39 - just like it's supposed to. VDI readings to me are only an extra - all you need IMO is a good, consistent audio signal for the dig/pass determination. I've also noticed that sometimes on a great-sounding audio signal I will get a VDI that doesn't match the full tone audio - all of those targets have turned out the be aluminum so far...

The reason I like "Full tones" so much is that once you get accustomed to the freq response of say, an "81" on the VDI your brain will link the audio signal and closest VDI from experience. This process takes a few months - I'm still learning as I go, but for the most part I can guess within 2 numbers of the actual VDI after I get the audio data through the phones. Deus's circuitry puts more emphasis on the audio signal than the VDI anyway, so at least for me relying mostly on the audio information has proven to work rather well.

I haven't found a reason to use Iron Volume in any other value than "0" for my style of coin/relic/jewelry hunting. Why would you want to hear a bunch of low grunts and blurps most of the time - while listening for the "70 plus" VDI audio signals during a hunt? I can see if you are trying to find a Civil War camp or the site of a sharecropper's shack in the middle of a 50 acre cotton field and having the iron volume up to 3 or 4...once you start getting iron hits then you can either reduce or kill iron volume completely and start hunting the non-ferrous items.
Another reason to have Iron Volume at "0" is due to the fact that low frequency sounds will scramble and distort high frequency sounds. This is why it is harder to follow speech in a noisy situation - most noise occurs in the lower frequencies, at 250Hz and below; while speech components vital to understanding occur in mid-to-high (1000Hz to 5500Hz) regions of the frequency spectrum. Anything that will hinder or block the audition of the higher non-ferrous tones will keep you from finding those targets - this part is a no-brainer for me!

Another observation about iron - The further the target is from the coil, the more difficulty the machine has with VDI -AND- conductivity. Take an iron object like a flat washer and scan it 8-10" from the coil and slowly move the item closer to the coil. Doesn't matter what freq you try this in - at fringe detection depths Deus and I dare say most other machines will have a hard time determining good targets from bad. The larger the target - the more total detection range it will have, and unfortunately many times the deeper it can register as a "good" target.

If iron-wrap around could be solved in a software update I would think Alain and his team would get the Nobel Peace Prize for that accomplishment! And then after that, develop software that will distinguish aluminum from gold

 

[samandnoah]

Great feedback, CZ. I'll explain why the iron audio when I've got a bit more time later. So, with iron audio = 0, what do you do when you hear a "scratchy" tone (for lack of a better term at the moment) that might be iron? How do you try to discern whether it's just iron, or a non-ferrous target near iron? Even went out for an hour this afternoon focused on 4 kHz and still had this issue. I can make just about any target sound good if I work at it long/hard enough at it!
Thx
Rich

 

[samandnoah]

Why Iron Audio on?

If you've hunted with an AT Pro you may have grown to appreciate what it can do for you. Remember, the AT Pro is pretty darn fast, and (if I remember correctly -- I can't find the link to the site that had comparative testing measurements for this) has the reactivity of the Deus at ~1. Even with that level of reactivity, when there is a lot iron in the ground the Iron Audio does 2 things. One, if you're swinging too fast or in an area relatively absent of targets, hearing the iron audio is a nice reminder to sloooooow down. Second, when you're in that iron, it helps you unmask and isolate the faint good signal (vs an iron false/wraparound) you may hear in and among the iron bits. In an environment like that, the AT Pro really is more of an audio detector than VDI driven.

Perhaps it is a faulty assumption on my part that having the XP Deus Iron audio on (typically only set to 1 or 2) would act/behave in similar ways to the AT Pro (and I had the same experience with the Eurotek Pro when I got to mess around with one for an afternoon. Loved that little machine, by the way. Super light, responsive, easy to use). Now, if you're going to hunt with Disc set at 2, I agree that there's much less value. I have not tried it to see if you hear iron audio for notched segments (like if you set disc = 2, and then notch 2 - 10).

I guess some of this comes from my early (frustrating) personal experience with the Deus digging in trashy parks with some of the basic settings where you have higher discrimination, silencer settings, and notches, and then my tweaking to higher reactivity without understanding what I was doing. Many of the target signals were clipped or difficult for me to get my head wrapped around. My first big improvement was REDUCING reactivity to 1, even in my trashy parks, so I could better hear/discern the signals. I found over time that I was doing much better when I had lower discrimination, no notches, etc. The downside of that is you can definitely get hearing fatigue. But with those lower settings I was also able to start raising reactivity again and comprehend even the shorter signals.

So, for all of that, I still find myself struggling when working in and ferrous objects and trying to unmask a good target vs discerning that it's just iron falsing.
Rich