Can we have a Mine Lab rep please respond to the questions posed below in the post about hot rocks

[digitrich]

as the question of proper noise canceling technique has come up as unclear and it would be a great help if you could clear this up for everyone. Specifically how to noise cancel, in the air, on the ground, or both?? And whether noise canceling twice, once in the air and once on the ground would cancel each other out or would they somehow blend together in a better result?? Or would a noise cancel in the air, and then finding a clean spot of ground and noise canceling once more with the coil on the ground be best? Would the major purpose of the first noise cancel in the air be done to make sure there was no interference while looking for the clean piece of ground or is there another important reason such as a more accurate blended result??

 

[Chris(SoCenWI)]

that noise canceling twice does no good. Noise cancel just shifts all the transmit frequencies by a certain amount ten times and listens for which shift recieved the least signals. Hold the search coil next to your headphones(on your head) and hit noise cancel. You can hear it shift.

Basically if you are moving your coil around or are over a target you will be causing signals to appear, Noise cancel will see these signals as noise and may not pick the quietest channel.

Everytime you noise cancel it will pick a new channel, or stay the same if that is the best; so doing it twice accomplishes nothing.

Chris

 

[NH Bob]

The answer you get from a Rep may not be the same answer you get from an experienced user like Sandy who hunts all the time as we do. It is also possible that they will not acknowledge the miss print so to speak. The last thing I intended was to get her in trouble for saying something she maybe shouldn't have. Which puts all the flack back on her.
My fault for bringing it up.

 

[John LA]

Electrical interference is in the air. You can pick up the signal in the air or on the ground. If you pick the coil off the ground you eliminate stuff in the ground while you are cancelling stuff out of the air.

 

[Rick(ND)]

From all my understanding of this noise cancel it is to check for any interference that may be from other detectors or any type of electrical interference and doing the noise cancel it will shift the freq a little and find the one that will run the quietest. You have to hold the coil very still while this is happening so it don't see any target response or it can not do a noise cancel correctly. Now if you did it on the ground after doing it in the air chances are it will see something and will change the noise cancel so now it can pick up that electrical interference you were trying to avoid. I always hold my coil about a foot off the ground very still and do the noise cancel on all my Explorers.
Many think this noise cancel is a ground balance, but it is not as the Explorer, Quattros and the Sovereign can not be ground balance from what I am understanding and why they work so well.

Rick

 

[NH Bob]

So in other words, I was told a bunch of crap by a Minelab Rep. Well so much for trusting the people at Minelab USA.

 

[mattockman]

If you listen to the words written...It is called noise cancel....Not ground balance.....its function is to tame the beast from near by noise...as in micro waves to electrical noise....etc......not ground balance......noise is in my work is chatter from electrical interference not ground minerals......I always thought the explorer had automatic ground balance.....so that being so...noise cancel is for the airwaves.......? traveling thru the air....not the ground.........all I care is I still find the old coins no matter what I do to noise cancel......I have good results when in a good location location location!

 

[mattockman]

n/t

 

[Chris(SoCenWI)]

n/t

 

[digitrich]

A second noise cancel should just erase the results of the first. Unless there is something we don't know??

 

[digitrich]

That wasn't crap they told you. If you were to noise cancel on the ground, the machine would then pick the quietest channel in that location (coil on the ground) and since that is how a person hunts (with the coil on the ground) it stands to reason that you would probably get better results doing it that way then in the air. As long as the ground you were noise canceling over was representative of the typical ground type and mineralization content of the ground you were hunting and did not have metal present under the coil, you should get pretty decent results. The amounts of electrical interference and ferrics (natural electrical interference such as lightning) change a great deal between a foot off the ground and directly on the ground. Detecting on a slope for example rather than flat ground can increase the amount of electrical interference by as much as ten fold. In some areas with high mineralization in the soil or very wet soils; those soils and moisture may help, themselves, to conduct some of your electrical interference and a noise cancel 12 inches above the ground could easily give you an incorrect result. The part where they said to noise cancel twice, that part was probably a load of crap. Disclaimer: These Opinions have been formed picking the brains of some electrical engineers who study electrical "noise" and are somewhat explained in Bruce Candy's white paper at the ML website. But they are opinions as we didn't seem to get any helpful advice from ML on this. I guess we will have to work it out on our own.

 

[NH Bob]

Quote:
That wasn't crap they told you. If you were to noise cancel on the ground, the machine would then pick the quietest channel in that location (coil on the ground) and since that is how a person hunts (with the coil on the ground) it stands to reason that you would probably get better results doing it that way then in the air. As long as the ground you were noise canceling over was representative of the typical ground type and mineralization content of the ground you were hunting and did not have metal present under the coil, you should get pretty decent results

I have been noise canceling on the ground since last year when I was having so much trouble with stability. Then at times I think I'm doing wrong so I'd cancel in the air.
When I talked with Sandy (who's been sick all last week) at the Show. She confirmed that canceling on the ground is a must do.
I will try to call her today and see if she will respond.

 

[John - Maryland]

n/t

 

[Great Republic]

I never noise cancel. It never seems to do anything at all. I just turn on and go.No problem mon.GR

 

[NH Bob]

When you do that, do you start up with the coil on the ground or in the air? Just curious.

 

[Great Republic]

Bob,
Sometimes I push the start button while it's still in the back of my van.Other times when I'm walking to the site with the coil in the air moving and with the coil on the ground not moving.
I've had my machine get a little crazy and noise cancel didn't seem to help. I just never use it and in three years of using ML Explorers first ExpII and now the SE I just never think to noise cancel.
Every now and then I may try it but when I do I'm not seeing any change from my normal detecting. Maybe there is something that I'm missing.

 

[NH Bob]

For lack of the right word I'd say that's uncanny.

 

[Great Republic]

Yes!

 

[migolddigger]

OK as I understand it, It all depends if your electrical interference if its in the ground or over head power lines. If your next to a cell phone tower above, and a power line below ground, I think you should noise cancel twice. It makes sense to me. Maybe if mineralization in the soil is an issue in your area, then thats where you should be noise cancelling. As I understand it the Minelab Explorer uses what is termed a time domain, not ground Balancing. In laymen terms, I believe it's getting rid of interference by using electronics through the computer inside. They use electronics to choose the best frequency's and thats the way I've always understood it. LOL. I have always listen to people with a wealth of knowledge, Sandy Burton being one of them, Cody being another. If you would like a better explanation the MineLab Explorer Classroom forum is where that could be explained better.

Tom

 

[digitrich]

Noise Cancel=(NC). If you go into options on the SE, under noise, it will tell you what channel your on. If you NC with the noise channel screen showing it will not tell you the new setting it has chosen until you go out of and re-open the noise channel screen. Only then will it update. When I NC'd on the clean ground, I got a different result then when I NC'd in the air nearly every time!!! This would demonstrate a definite case for NCing on the ground. Apparently there is a definite difference in the type and amount of interference between ground level and twelve inches above that same spot in the air. I did this experiment in a farm field, so there definitely was no underground power lines. Interestingly though, if I walked ten feet and hit NC again the machine most often chose a different channel, So often in fact, that it really made me wonder if the whole NC thing is nothing but hyped up nothing. Who is going to noise cancel every ten feet in a corn field???? or any where else for that matter??? Now, just maybe, I was unlucky enough to find the Bermuda Triangle of all corn fields, but in every channel the machine stayed stable. It could also be that IF there is little or no interference that the machine just picks a random channel. Some of you with test gardens might be able to manually adjust your noise channels and test how the different channels effect your performance. I didn't get a chance to throw on a small coil and NC over iron and then try picking through the dense iron trash spots, I am going to try that next time I go out there. I am pretty curious as to what will happen.