EMI and mineralized ground

[epi-hunter]

Hi everyone,

I have logged probably 15 hours on my new E-trac. Prior to this I had a SE so that helped with the learning curve.

My question relates to conditions of extreme ground mineralization and also EMI. Here in Kentucky, at the parks that I was using the E-trac, I found that frequently, EMI was a problem and despite using noise cancel, I was forced to lower my sensitivity setting. But the bigger concern I have is ground mineralization.

Using autosensitivity +3, the E-trac was running between 18 and 19 at these sites. I tried manual sensitivity, setting it in the low 20's, but the falsing was just too severe so I backed off. What I am finding is that I am unable to get the depth that I want in this ground. I'm not getting solid signals (or any good signals) deeper than about six inches. And at that depth, I dig nothing but clad.

My question is -- does anyone have any ideas as to how I can better compensate for this ground mineralization? I'm using the stock coil, which should be the best coil for this type of ground. I have the gain set at 28, using multi-tones, long, and variability and limits set at 29 and 30 respectively. I'm using Andy Sabisch's coin hunting disc pattern.

Do I just need to crank the sensitivity and learn to live with the falsing? I know that the optimal way to run the E-trac for best performance is "on the edge" meaning that I should have some falsing. But this really seemed excessive.

Any hints or ideas would be greatly appreciated.

Angie

 

[epi-hunter]

17 views and no response... must be a tough question.

 

[coinnut]

Hi Angie, I would try and use the ferrous sounds setting vs conductive. Also switch to 2 tone (or 4 tone) instead of the multi tone. Watch your numbers as to what's silver (exa 12-46, 10-46, 8-46 etc,...). This works for me as the falsing is easier to handle. It does false a lot when you crank the sensitivity in bad ground. I know that the DD coil is supposed to be the best coil for mineralisation, but sometimes I think that the concentrics would handle the falsing a bit better. I hear that 6x8 SEF coil is pretty good, wonder if it handles the EMI and mineralisation better??? ANYONE???

 

[gibsondan]

I don't have any EMI problems with my E-trac. It runs nice and quiet. I have hunted a few areas where the sensitivity almost completely bottomed out. My solution was to bump manual sensitivity up to +3. I stay in manual because I get better depth than in auto. If I were still getting too many false signals, I'd just move on to another site. Here in Ohio the only time I've had this problem with ground mineralization is with fill dirt at a couple of sites.

 

[TheMarshall]

Hi everyone,

I have logged probably 15 hours on my new E-trac. Prior to this I had a SE so that helped with the learning curve.

My question relates to conditions of extreme ground mineralization and also EMI. Here in Kentucky, at the parks that I was using the E-trac, I found that frequently, EMI was a problem and despite using noise cancel, I was forced to lower my sensitivity setting. But the bigger concern I have is ground mineralization.

Using autosensitivity +3, the E-trac was running between 18 and 19 at these sites. I tried manual sensitivity, setting it in the low 20's, but the falsing was just too severe so I backed off. What I am finding is that I am unable to get the depth that I want in this ground. I'm not getting solid signals (or any good signals) deeper than about six inches. And at that depth, I dig nothing but clad.

My question is -- does anyone have any ideas as to how I can better compensate for this ground mineralization? I'm using the stock coil, which should be the best coil for this type of ground. I have the gain set at 28, using multi-tones, long, and variability and limits set at 29 and 30 respectively. I'm using Andy Sabisch's coin hunting disc pattern.

Do I just need to crank the sensitivity and learn to live with the falsing? I know that the optimal way to run the E-trac for best performance is "on the edge" meaning that I should have some falsing. But this really seemed excessive.

Any hints or ideas would be greatly appreciated.

Angie

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Hi there Epi.

If your auto is running at 18 /19 with a +3, then that is 15 to 16 normal. That doesn't suggest a heavy mineralized soil to me. (Fe wise)

Is the ground 'boggy' or wet ????

With the auto sense levels you've quoted, the max depth on a one inch diameter coin will be about 8 inches in theory.

The suggestion that you are in a region of bad EMI is a more critical factor.

Are you able to see any visual sources....radio masts etc???

Multi-tones ...Long.... Hell, you are an audio masochist, under the circumstances you describe.

Are you hunting in Conductive audio? If so, then 4 tones and Peak hold or Normal would be my preference.....but each to his own.

There is nothing you can do to counter mineralisation.....other than to sweep as parallel to the ground as possible, and maybe a little slower than your normal speed.

Sensitivity.....only you can judge that one for the location you're searching, and the the idea that you crank up the sens. 'and live with it' suggests to me that you have limited understanding of the realities of detecting. Sorry if that comes across as a blunt statement, but it does reveal why you are having difficulties solving your problems.

Alternative thoughts.....If there is any Ham Radio station locally,transmitting on 'side band', then that will cause havoc for you.

Hope things improve...................TheMarshall

 

[Gaz]

Angie,

Try to move away thinking that you have to crank up the Sensitivity to get maximum depth. It is much better to make the ETrac run stable. Do not be afraid to drop it and stabilise the machine. The loss in depth will be negligable compared to the popping and chirping. You are more likely to miss targets amongst that popping and chirping.
Personally, and I mean personally!!........I can't get on with multi tones. It's just too busy for me.
Try these settings the next time you go out. (You can always go back if you don't like them). I use these quite a bit.

You guys don't have to worry about missing thin silver hammered coins so.........
Go into quickmask.........bring up the FER to 32 and the CON over to about 5. (That should nip out the Iron and the silver paper. Watch the conduct however, you could nip out very small gold).
Use either 2 or 4 tones. (I like 4)
Use Conduct sounds.
Use Manual sensitivity, it's better!! Watch the "suggested" Manual setting and slightly better it a little. If it starts falsing, back off until it stops.
Dig every good two way repeatable signal. If it isn't iron and silver paper.............it's fair game!!

Hope that helps,

Gaz

 

[jbow]

Hi there.

I am in Bartow county GA and we have severe mineralization, (iron hills). I run auto+3 in most places with no problem. +3 usually runs between 18 and 22, sometimes lower. But it is fairly quiet..

Try this. Switch to the relic patters, ferrous, 2 tones, difficult ground, high trash. Gain 22 or so, set the threshold tone to 19 if you use conductive.

I use this to hunt both coins and relics. Shallow targets will get a good two way tone even in trash but deeper goodies will be iffy in trash and iron. The trick is to check the TID on all the high tones, (in 2 tone ferrous), and pay special attention to the conductive, 2nd number. That number will lock onto the good target, it may jump to the trassh but the good number will be there and usually from one direction you can wiggle it in to a steady number. Those are the good deeper targets that other detectors are missing. You'll get it, just don't go with an open AM scerrn like with the SE, the ET works better with a little disc.

If I am at a ballfield or somewhere newer I may use conductive, multi tone, and a coins pattern but I also like to use the relic pattern with conductive, multi tone if there is only clad. But... if there is older stuff there I always use ferrous 2 tone and study the response on the conductive number. If the ferrous number never drops below 30, it's usually iron but sometimes a good target will have a higher ferrous number because of iron in the hole. I dug a flattened eagle coat button last week in a "hunted out" park. It read 20-22 or there about, I don't remember exactly where it jumped to but it was mostly 20-22/23. When I got it out of the ground it was 12-22.

You may have a bad machine too if your Explorer works well, no EMI, in the same place. Can people run an F75 there? If so, i'd suspect the machine. Try your Explorer coil on it and see if it is quieter.

HH,

Julien

 

[epi-hunter]

Thank you for your reply. I actually used ferrous sounds on the SE and liked it, but with the E-trac, because the ferrous numbers on good targets are all so similar and at the 12-ish mark, it seemed like conduct was the better choice. I can see using ferrous at the beach, where most of the good targets are mid-range, but coin shooting?

I did love not digging iron with the SE....

 

[epi-hunter]

Thanks, I appreciate the advice. However I didn't mean that I would crank up the sensitivity and "live with it". Where exactly did I say that?

I know that too high a sensitivity is just backfiring. It's not a linear proportionality --- increase sensitivity, increase depth. What I meant is that for maximum effectiveness, running the sensitivity at a level where you hear some falsing (and recognize it as falsing) is what many good detectorists do.

 

[epi-hunter]

Wow, apparently I said something in my first post to lead everyone to believe that I think cranking up the sensitivity will give proportionally increased depth right up the graph.

I do understand that running the sensitivity too high is just shooting myself in the foot. Compared to a good friend of mine, who is very successful at this I might add, I am not able to run my sensitivity to anywhere close to his levels (manual at 2. He lives in a different part of the country. I was trying to see if there were any other settings that might help add a little depth, since I am digging clad at seven inches.

I have always used multi tones. I prefer hearing the subtle differences.

Thank you for your advice... I appreciate it.

 

[epi-hunter]

Thanks very much -- I'll try this. I don't know if I can use two tones, being used to multi tones (with my SE, too) but it's worth a shot.

 

[epi-hunter]

Thanks. I've tried several sites here and seem to have the same issue at all of them, so I assumed it was the ground. But I'll keep trying.

 

[jbow]

Well, if you want to use conductive/multi tones try using the relic pattern if there isn't too much trash. I use it at an old football field turned soccer field and find plenty of coins. If you set the threshold tone at 19 it will match the conductive high silver tone. I use max limits and variability on conductive. I guess you've noticed that it does not have as many tones in multi tone ferrous as the Explorer does.

I do really well using the ferrous/2 tone and watching the conductive number. Dig some iffy signals that hold a good conductive number even if it goes away when you swing from another direction. You'll get some surprises. The key, IMO, to success with the E-TRAC is the conductive number. That is it's strength, they straightened the conductive line as oppossed to the curved line on the Explorer and it is really accurate, even at depth. The Pro coil really seperates the goodies from the iron and trash. I have found good targets that were only one way signals but they were consistant on the conductive number from that one way. The "wiggle" helps. If I can wiggle in a good conductive number I will usually dig it if the ferrous number is below 25 or sometimes 30, especially if the targets are deep. Remember, the ferrous number can be anywhere but not usually above 30 and, on the ET, the conductive number will stay really close, if not right on the proper number, even at depth. So... a 12-44 is almost always either a bronze penny or a clad dime, so is 13-44 and 18-44 and 20-44... etc. there is another thread about 1-32 numbers. Some are finding them to be IH pennies on edge. 1-40 is the reading for a Morgan dollar. I have a long list of numbers, some that I complied and some I copied from others. If you want i'll try and copy it. I find that 11-11 is almost always a square tab, sometimes 12-12 is a square tab and sometimes it's a nickel, but 12-13 or 12-14 is almost always a nickel. 12-15 is almost always a tab but some cuff buttons read 12-15 too. I just dig a lot at a site until I get an idea of what is there and what it reads.

If you just remember that the conductive number does not vary much, if at all, the ET will begin to make more sense. Also, I haven't seen much if any advantage to manual sensitivity. Auto or Auto +3 or even Auto -3 work very well and get depth. Sometimes I will set manual to 28 and switch over to it to check a weak target, sometimes also switch to an open quickmask screen. But sometimes I set the manual sensitivity to the level the machine says is optimum, which may be 10 or 12, hunt in auto +3 and switch to the lower manual sensitivity and sometimes it gets a clearer signal. Try everything. Just remember, the ET is not an Explorer. Don't try to make it be one.

HH,

Julien