Just Had a Very Eye-Opening Experience With My Explorer II...Long, But Worth The Read.

[Mike (Virginia Beach)]

And that experience was right in my backyard!

I have a test garden, running along the rear of my backyard in front of my privacy fence. I have about a dozen targets buried out there, about 3 feet out from the fence and at least 3 feet apart. All along the fence I marked with a Sharpie pen (and have had to "refresh" the markings a few times) what is buried there. All targets were buried at least 5" deep and several at 6", 8", and one or two at 10". They've been there for over 5 years, so they have a little "halo" going, though certainly not as much as some of the stuff we seek out there does. I have a minnieball, musketball, silver and clad dimes and quarters, a nickel and a penny.

When I planted these targets I had my first machine, a Garrett GTAx 750. I didn't realize at the time that there was a power line a few feet from my dig spots, further out and much deeper. I found that out a few years later when they dug it up for a repair. Anyway, I could hit SOME of the targets with my Garrett, but not all. I subsequently got a DFX and hit the garden with it. I got more of the targets, but not all. And it was clear there was SOMETHING in the ground at that time, because with the DFX it was a bit unstable in that area. When I got my CZ-70 I was able to get all of the targets, which is a lot easier when you KNOW where they are than when you don't. And it took some work, but I could hit them all. And not being a threshold machine, it was completely stable...at least it seemed so, because it's either "hitting" or it's not. Then I got the Sovereign Elite. With practice and tweaking I was able to get most of the targets, though with a little less certainty than the CZ. I should also note that a few of the targets with the CZ were also "iffy". The last machine I tested out there was the Quattro, which I had about this time last year. It did well too...better than the Elite, not quite as good as the CZ, and pretty unstable due to the power line as well as probably some house construction trash from about 1980 when my house was built...that test garden definitely represents some of the hunt sites I have hit in the past that are iron-rich, trashy, or have EMF issues...a challenge for any machine and some do better or worse than others.

Enter the Explorer II. When I got that machine I didn't take it out to my garden... didn't really think about it. I took it out to some heavily hunted sites that I had done well at with all the other machines and did well with the Explorer II. And I feel I caught on to it fast, thanks to these forums and folks like those that post here. I really like Charles' program and I link to it frequently. I like to run in IM -16 a lot and I run the sens in manual as high as I can and stay semi-stable. A lot of my hunt spots like woods and fields DO like sens at 28 and run a nice threshold, so I run it there. I have dug and posted quite a few nice finds that were from very respectable depths. Once I hunted an old home site I call "The Barber House" because of all the great stuff we've found there over the years, including many Barber coins, CW and RW buttons, and even a 1793 coin. The place is a TOUGH HUNT, iron in every swing and lots of roof tacks, etc. I commented on the Explorer forum in my post that day that I had found some things that I passed over previously by dropping my sens to 24 and even 22 and was hitting some stuff that would disappear when I raised it up. My buddy JW at KellyCo told me at the time to try lowering it to about 18 and you'll really be surprised. Well I have to admit thinking "Heh...THAT'S not going to happen...", thinking that was a tad low to be of any value unless maybe I was under a cell phone tower.

Well, he may have been right, it looks like. Because today I got a wild hair and decided to take the Explorer outside and check those targets, many of which are clearly deeper now because the CZ can't hit them all like it used to. I had the Explorer II in IM -16 and running sens 25, Gain at 7 and it was a carnival...all kinds of noises and unstable. I hit the first target, the musketball and got a really BAD signal that I would have never dug. Raised the sens a little, lowered it to 22, put it in 25 at Auto, went to a disc pattern that would hit a coin or a bullet...I was able to improve the signal only marginally. So I moved to the silver quarter at 8". Here I got a silver tone and in Smartfind or Digital I could "work it" to convince me to dig, but the audio as well as the display was all over the place and inconsistent. Had I not KNOWN what was there, I would probably have never hit it in the first place, no less dug it. I went from target to target and they all sucked, basically. I remembered how in that other really bad site that lowering the sens had helped a lot, but low should I go??? I was at 22. So I went to 20. The target that a moment ago was a all over the place stabilized out nicely and was giving me nice tone, nice Smartfind, and nice digital. It was a Merc dime at 7" on the fence marking...it showed around 10 on the pinpoint and was "barely there", doing that "pulsing" pinpoint you get on the deeper targets, rather than a solid one...where you KNOW it's a coin...it was a definite DIGGER! I went back and hit all the other targets and they were all GOOD....ALL DIGGERS! And here's where it gets REALLY nuts...I lowered the sens to 18 and they all got BETTER, a couple of them reading at max depth on the meter and almost out of pinpoint range completely. And yet, the signals were near classic. I was very excited, I have to say. I dropped it a little more to 17 and then 16 and 15 and it was downhill pretty much on most of them when I went below 18. But 18 was OPTIMAL at THIS SITE. So what I learned was that I have several sites that I need to now revisit because they are worse, as bad, or close to as bad as my test range. And I have a new respect for this machine, because in the past it was my feeling that if I was running less than 24+ I was certainly missing stuff. I now know that sometimes you miss stuff BECAUSE you're running 24+, or even 20+.

I know this is a long post, but I thought it should be shared. I've been hunting with this thing for many months and doing well with it, but have often thought it would be nice if it were a little more stable. Running the sensitivity down that low made it MUCH more stable and it still had incredibly impressive depth. But the real story is the target masking that was occurring at the higher sensitivity due to the rough ground. I'm REALLY looking forward to hitting a couple of sites I had thought were DONE because I'm now sure they are NOT. I know that this is normally lower than what we all would like to run the sensitivity at and I will still run 28 in my clean spots, but I learned a valuable lesson today...there's no benefit to running high sensitivity if the ground you're in is too hot for the machine to handle it.

 

[Ray Hogan]

Thans for sharing that info...by the way, how can I see the "Charles Rock Solid Setup"?...my link doesn't work anymore...thanks, Ray.

 

[hoss3500]

A real great post,just for info I run my exp2 and the quattro between 15-18...Sandy at minelab metion that about a year ago and that where it's been ever since...

 

[Mike (Virginia Beach)]

I think I was guilty of running my Quattro too hot as well. I did well with it but I rarely ran it below 17 on land and 18 at the beach. I think I would like to have tried it a little lower at some of those hotter spots. But now that I experienced this with the Explorer II, I'm pretty excited about pulling a few more good finds at a few spots.

 

[Mike (Virginia Beach)]

Try going to this site and look at the "Explorer Tips" section, particularly the "Machine Setup" part. It's very close to the same thing and there a lot of other good stuff there too.

http://www.detectorgear.com/index.htm

 

[Charles (Upstate NY)]

First I apologize if this keeps you up thinking late into the night.

This may be a rule of thumb or it may be an exception to the rule. Be careful about doing a classic "me" which is to make an observation in the field then rely on it as a rule of thumb only to find out later it was just an exception to the rule e.g. it holds true in some cases, but overall is more often not true.

We have conflicting field data...

I know from many many tests that a deep target gives a good signal with my sens at 26, iffy at 24, vanishes at 22. This conflicts with your findings.

I also know that sometimes when I get an iffy target with my sens at 26 and I bump it up to 28 to see if it improves, instead it vanishes altogether. So I turn it down to 24 and it actually improves to a good signal. This confirms your findings.

So you have to play the odds, the question is which approach will result in more finds? Over time I would have to say a higher sensitivity has produced more finds. But give me a reason to lower my sens, tons of iron at a cellar hole for example, sopping wet ground with iron, or in your case nearby EMI from power lines and most definately I will lower it.

In this case in particular I would be careful about drawing too many conclusions until tested further. EMI from power lines resulting in the cursor jumping all over the screen is rather an extreme case study. When I speak of running my machine hot, my cursor is pretty stable, it might jump on me once every few seconds not 10 times a second.

There is only one site condition where I will run the machine totally unstable like that and oddly I got different results than you did. I was out in Oregon at a 1800's park. The soil is infested with mangnetic black sand and its difficult to get any depth. I had been detecting around this old statue for about 30 minutes with zero luck. I had my sens about 23-24 and the machine was stable. Frustrated by the lack of finds and this was my last hunt for the trip I got irritated and cranked the sens to 30, maybe to its max. Well the machine went nuts beeping and the cursor was all over the place but...when it got it over a coin it locked on and so long as I did the micro swings back and forth over the coin I could hear it through all the unstable noises. I backed off the sens to pinpoint, the coin vanished. I dug 3-4 wheats and 2 mercs from around that statue with the machine completely unstable.

Here's something else to think about. The Explorer is transmitting at 100% power no matter what you set your sens or anything else to. Therefore the whole of the signal at 100% power exists in your machine. What you are doing by way of sens and other settings is slicing and dicing this signal up so that you hear only what you want to hear. In this case I think you lowered the sens enough to chop off all the EMI. The coins, being a stronger signal than the EMI were still there. I used this technique sort of with a large coil on a wet saltwater beach last season. Instead of the sens, I lowered the gain, which lowered the salt falsing to a point of barely audible while the coins still banged through hard in my headphones.

The Explorer is sometimes a wierd beast to understand. Here's something odd that confirms your findings. I noticed at the beach that a near surface quarter can give a pitiful signal, I'm talking crap. I raise my coil several inches which has the same effect as lowering the sens and the quarter is screaming solid. Go figure.

The only thing I'm really sure of is there seems to be an infinate number of situations where targets don't react as expected.

 

[Charles (Upstate NY)]

I think the main point of my long winded reply above is this. Be careful about associating the sens setting with power applied to the target in the ground. Not that you have done this but I thought this way once upon a time and so I mention it.

If you connect the Explorer to an oscilloscope you find that the transmit signal does not change regardless of what you have your sens set to. 1, 18, 28 it doesn't budge.

Therefore reducing sens when you think a target is being overpowered by a high sens setting really doesn't reduce the power transmitted to the target. Its simply lopping off weaker parts of the signal internally.

 

[Mike (Virginia Beach)]

Charles, thanks for that insightful reply. You of course make some great points. And as I said earlier, my habit is to run as close to 28 as I can in most of my spots. But at at least one other spot I did notice better performance when the sens was lowered than with it up, despite the fact that I thought that my threshold, combined with my slow sweep and patience, was allowing me to run it higher. In fact, iron/trash-masking was working against me at the higher settings.

I've also noted your example of the horrid response to a coin on the surface in the past...sometimes these things make little sense. Like sometimes I'll have a prominent silver signal that I KNOW is silver...likely a dime. And when I dig my plug and sweep it and get nothing and then sweep the hole and get nothing, I KNOW it's a silver dime...that has fallen to the bottom of the hole and has had it's halo broken...and despite being no more than 5 or 6 inches deep, is suddenly GONE until I retrieve it. Seems like you would still get SOMETHING from it...and often you do, but often not.

To sum up, the only thing that's certain is that NOTHING is certain. So many factors affect the way our machines act and react. Suffice to say I have at least learned that with sensitivity, MORE isn't always BETTER.

 

[GraveDiggerMax-VaBch-Va]

have never hunted above 18..............trid 24..........22........20, but have settled on 18 for long long time.

mike

great post and thanks for sharing it............maybe more will catch on..................but maybe they will not and leave more for others.
max

 

[Dok-Ath]

Every time on the new spot I am burying a small coin ( like penny ) at max depth, abt 4in and adjust the ExpII to most stable sounds. Usually Gain 10, Ferrous, Deep On and just for me Threshold=0 ( silent mode ) HH

 

[Cody]

I have talked to Minelab several times about this and was told that is why we should set the sensitivity as high as we can with stability and use Semi-auto. I understand it is noise to signal ratio as measured by the electronics. In situation where a sensitivity of 18 is best based on the signal to noise ration then that is selected but when 28 is best then that is selected. There has been a lot of debates on this but they insisted that semi-auto with the sensitivity as high as it would go with stability. Well, I can just about always set the sensitivity to 28 so do so. If they are correct about semi-auto and manual then using semi-auto will compensate for the variables.

HOWEVER, when using manual I can sweep the coil a little slower and have detected ultra deep target but when I switched to semi-auto I could not. I think it was Ralph at SunRay that said that when I switched from semi-auto to manual I had to sweep the coil over the soil a few times so the circuits would compensate then go back over the ultra deep targets and I would hit it just fine. I gave that a try and sure enough he was correct so I was mistaken in thinking I was detecting an ultra deep target in manual that I missed in semi-auto. Anyhow, the more I read the post about where to set the sensitivity from 18 to 28 the more I think semi-auto may be correct. If I have it set to 18 and it kicks up to 28 or the other way around then it is compensating for various environmental and soil conditions. But there is the question of how well does semi-auto respond to changing conditions. I have tried both many times and do well with semi-auto or manual although semi-auto is much more stable.

Again, Minelab was very insistent that max sensitivity with stability and semi-auto would work best. It is up to the user as we know but they may be correct.

 

[Mike (Virginia Beach)]

Well that certainly is food for thought. I have to say that although I tried running semi-auto yesterday at 24, 25, and 28 and got poor results compared to manual at 18, I may not have given it enough time to adjust. That said, it WAS getting excellent signals off of items at 8" give or take at manual 18.

I'll try to do some additional testing after work.

 

[RingProfessional]

Great post!. I am working a park out at the moment i will try different sensitivities from now on.

 

[Charles (Upstate NY)]

This like so many other things is not 100%. At times I run my Explorer so hot that I switch to semi-auto to settle it down just to get a more stable target ID or to pinpoint. Sometimes I get a perfectly acceptable signal. Other times I get no signal at all and I sweep it enough for it to do whatever it needs to do internally.

I know from experiments in the field that semi-auto can overcompensate trying to provide you with that super clean, stable threshold. Some soil types around here are a bit noisy. I have manually adjusted the sens to a really good quality threshold, then let semi-auto have a go at it and in testing found it lowered the sens a many points lower than I did. I saw no reason to lower the sens to that level just to filter out those tiny faint ground signals one would only hear if they cranked their gain to 9 or 10.

So its tricky business this semi-auto. Given the right conditions I'm sure its a perfectly good way to go. In fact it may keep you from missing those targets that seem to vanish when the sens is too high. But wander into an area of EMI, noisy soil, etc. and you now have no idea how low your sens is. Maybe you are walking around with your sens at 10 for all you know and in areas I hunt thats a waste of time, the stuff is too deep.

What we have here is an opportunity for minelab, something I have not seen suggested before. Find some space on the screen to display what semi-auto has set the sens to!!! That way I can glance down at times and see how its compensating and if I think its too low, at the very least I could switch to manual to determine why semi set it so low and run manual sens in that area perhaps.

Charles

 

[Cody]

I called Minelab to discuss semi-auto and manual and they told me I needed to discuss it with the engineers in Australia. I think that was about as nice of a way as I have been told to get lost in a long time. Ha

 

[Mike (Virginia Beach)]

>>> What we have here is an opportunity for minelab, something I have not seen suggested before. Find some space on the screen to display what semi-auto has set the sens to!! <<<

You mean EXPLORER III???

Or can we do it with a firmware update? No, I suspect we would have to have a new LCD, so we'd be talking "backfit" package. Probably cheaper to keep us guessing.

As for semi-auto vs. manual, I hear you on running around at 10 and not knowing it...that would be my fear. But that fear has certainly cost me some targets already, not wanting to lower it down from 24+ for fear of what I might be missing. I think I will be doing a little more field experimentation as I detect new sites, to see how the sensitivity affects the quality of my signals...both manual and semi.

 

[Mike (Virginia Beach)]

I frequently find myself wondering why some of the Minelab tech gurus don't have a presence on this forum, to answer a question of two at times like this. But I guess if they supplied that kind of a "man behind the curtain" it could quickly become a fuill-time job.

 

[Cody]

They had a guy come on from Minelab and say we would be better off using Semi-auto and something to do with Deep/Fast as I recall. The guys on the forum jumped all over him and told him he did not know what he was talking about and were ugly in doing so. As far as I know that was the last time he came on the forum.

 

[Cody]

I went to manual simply because I am uncertain what semi-auto is doing. I think from how I set the detector up I do know what is going on with manual and I do run with a constant threshold.

 

[Mike (Virginia Beach)]

Yeah, I can see that happening too. As we know, we have our fair share of opinionated folks in these places. Usually it works out to be a GOOD thing, if we can keep the egos in check.