MXT Coils & Tuning For Coins

[tvanwho]

I like the 6 x 9 coil for prospecting altho I believe it is a DD coil ,and since I don't have an extra lower rod, I just keep the 6x9 on all the time.I also hunt coins with it. Which coil are you using for your testing? I guess I am also wondering in the field, how many coins are actualy deeeper than 8-9 inches?

    Altho, in a park in Wisconsin, I dug up a wheat cent at a bonafide 12 inches using a Tesoro Tejon. My entire Lesche digger was in the hole when the coin popped out. It was grass on top, and dry dirt underneath, late summer.That was the deepest coin I've ever found. But the Tejon was an iron magnet so its gone. If it had had the modulated audio like on my Lobo I might have kept it. But no matter if the target was an inch deep or a foot deep, was always the same beep.12 inches with an 8 inch coil is pretty darn good tho and in the ground, not an air test.

[auminesweeper]

I have the 10" DD coil but I have hit coins around the 12" Mark and bigger coins a bit deeper, My mate hit an English penny at 13 and a half inches Plus with his MXT using the 12" and he only had the Gain at 6.5 In a ploughed field,, I have done similar but not quite as deep as him, I have dug many coins over the 12" mark using the Old 9.5 coil, the 5x9 and the 3x6 coils are the best for prospecting, But near the surface the 10DD will hit very tiny bits, I think they are impressive coils but I prefer the 9.5 and the 12", and the MXT was Calibrated around the 9.5 and that was the Coil that Whites wanted to be the standard coil for them, But they are all Good, That 15" one I have it the deepest Coil I have ever used It will do what the 20" DD's do in mild ground, But it is not an everyday coil and it too can see bits as small as 0.03 maybe 0.02 grams at a pinch, Unlike DDs it does not seem to lose sensitivity, Its great for fine jewellery  but not very good to use in hot ground where Gold is found. 

According to Dave Johnson and Co, a coil should be able to hit coins at about twice their size in depth, But in average ground I have found a Concentric can and will hit coins at about 1 and a 1/3 times their size in depth.

IE that little 6" (5.3 ) coil will hit coins between 7 to 9 inches +/-

john

 

hope this helps

[tvanwho]

Could you tell me how you setup the controls on your MXT for this world class depth in ground? One thing I dislike about my machine is I always get confused with the dual control knobs and 3 position trigger switch ,so just set the knobs for the white  triangles on average. I've read MXT books but still get lost. One nice thing about my Garrett Ace 250 is that its so EASY to figger out and almost idiot proof and still gets coins at 6-7 inches. I grab it more often than any other detector...

 

-Tom

[auminesweeper]

Tom my setting are nothing special, I have loads of links to post explaining setting the MXTs up for different Tasks / Areas etc so I will send those Via PM in fairness to Steve,

When it come to Coin Hunting with the MXT I use the Relic mode,, If your MXT is the MXT E'series or the MXT 300, use the Relic mode with the Trigger set in the middle, The reason I do this is because it has a slower SAT speed and I can run the Gain up Higher, A simple way to prove this to your self is to set it up like that and run the Gain as high as you can just as it starts to get noisy, NOW switch it to C&J or push the Trigger forward and see how noisy it gets then back the Gain down to where it runs smooth and now look at the Gain pot and see how much you have turned it down, Apart from the Prospect mode I never use the other settings, You can either tune the Gain like prospectors do and run it noisy or tune it just before the edge of being noisy,

Now I used the 12" coil in a junk filled site because everyone had hammered it with XPs Tesoro's, Minelabs, you name it had been hammered by every detector made/sold since 1967 and even Detector REPS from all the companies had used it as their Demo/Test site for The Once biggest dealers over here and I worked out that because of all the junk no one had ever used a big coil on the place where you can hit 10 or more targets in one sweep of the coil and my sovereign GT was useless there because of the Iron mask and my E-Trac behaved like it was on LSD, and I only ever found one coin there using them in about 18 months until I wised up, so knowing the trouble I had and thinking others must of had the same problem but they were trying to get by with smaller coils and I even tried that too and still Nothing,

Anyway I bought the MXT 300 and being short of cash off I went using the 12" Coil and I picked a spot on the edge of the woods and in the first sweep of the Coil I found 3 Gold Items In one 4 foot sweep, One at the start and 2 about a foot apart at the other end of the sweep, I marked the targets and then dug them, Happy Days    .

To find those deeper Coins/Items Ignore all the stuff where people say In junk filled sites you need a small coil because don't forget that most sites have been hammered by every man and his Dogs best mate and because of the junk they switch to smaller coils, I use the 12" coil and when I have gone over the place a few times I then switch to a smaller coil.

When you set up your machine take a 2 and a haif or 3 inch nail with you and after you have GB'd your machine throw it on the Ground and set your disc so it just knocks out the nail trying to keep it as low as possible If it makes a low tone at 2.8 try and set it at 2.4 or what ever the lowest setting it will go is, it should be somewhere between 2 and 3, you will dig a little more Iron but not enough to drive you nuts

So Turn on your machine with the gain at about 3 to 4 In the Relic mode with the trigger in the middle and Ground balance but don't put the coil closer than 4 to 5 inches to the ground, this sets the GB a bit more positive and Lock the Tracking, Now throw down your Nail and set the DISC, Now turn the Gain up to where it starts to run Rough and then back it off just a touch so it is right on the edge and off you Go, and that is all I do

Now I know the MXT has built in warnings about ( REDUCE GAIN LIFT LOOP ) so you do not Overdrive the Return signal But if you Drop the Gain down which it totally ALIEN to us all, But with the MXT it will process the signal better and ID Targets more Correctly and it will still Go as Deep, You can Try this your self with a quick Air Test just to see how much this will effect the Depth but remember the depth is reduced in the ground so turning down the gain will have a lesser effect because all signals are restricted by the soil anyway.

IE, So if your 6x10 is hitting coins at 8 or 9 inches with the Gain set just before where it runs rough, Now test it doing an Air Test and then Strap on the 12" and set the Gain to the max again now lower the Gain so that coil reads the coin at the same distance as the 6x10 does, and then look at the Gain knob and see how much lower it is and that shows you the power Reserve that you have left, So by setting your Gain anywhere between there and maximum is all free and setting the gain within the 2 settings you know will add  extra depth, Don't forget that the Ground can stuff that up but if the soil reading gets up to around 70 - 75 then the 10 DD comes into play because the 12" concentric will start to loose depth, The Ground reading where that deep coin was found varies between 64 to 67,

Going back to that site for a minute, People had been detecting there for 34 years at the time and yet I found a Roman Villa there just by going deeper, So don't get sucked into that small coil thing because it does pay to think out of the box sometimes, NOT all the time, But when the finds are thin on the ground so to speak it pays to do the opposite to what everyone else does,

Oh and if you want to check your MXTs recovery Speed/Rate put it in the Prospecting mode and put 6 coins in a Row. Starting with each coin being 6" apart and sweep the coil over them and then move them  closer at an inch at a time and you will hear it give a machine gun effect as you get them closer together sweeping at normal speed and the faster you sweep the faster the it makes the sound.

Hope this Helps,, Good Luck.

 

John

[auminesweeper]

On 2/14/2016 at 11:17 AM, tvanwho said:

I like the 6 x 9 coil for prospecting altho I believe it is a DD coil ,and since I don't have an extra lower rod, I just keep the 6x9 on all the time.I also hunt coins with it. Which coil are you using for your testing? I guess I am also wondering in the field, how many coins are actualy deeeper than 8-9 inches?

    Altho, in a park in Wisconsin, I dug up a wheat cent at a bonafide 12 inches using a Tesoro Tejon. My entire Lesche digger was in the hole when the coin popped out. It was grass on top, and dry dirt underneath, late summer.That was the deepest coin I've ever found. But the Tejon was an iron magnet so its gone. If it had had the modulated audio like on my Lobo I might have kept it. But no matter if the target was an inch deep or a foot deep, was always the same beep.12 inches with an 8 inch coil is pretty darn good tho and in the ground, not an air test.

With you hitting 12" with an 8 inch coil shows you that what I said about a concentric coil Averages 1 and a Third times it's size in Depth, and the reason your 6x10 hits coin at 8 to 9 inches is because it is a DD, Now because of it's shape,

 To find its possible Depth of the 6x10  do this,, 6  + 10 = 16 divide it by 2  =  8 inches, DD coils depth is more related to their size so if you have a 10" DD then that is 10 + 10 = 20" divide by 2 = 10 inches.

With a Concentric they tend to give a Depth of 1 and a third times their size in Depth, So a 12" concentric coil in theory can hit coins at 16 inches, So that's 12" + 33% = 16,

Now just for a second go back to that MX-5 in that Video Remember it was running the 9.5 Concentric yet it saw the coin at 10.5 inches, now take away the 33% that the concentric adds to the depth or a 3rd of that by using a DD so the Actual depth would be closer to 6.93 inches., Not 10.5, inches.

I try to use a Concentric Coils as much as possible because we all crave the extra depth from our machines but we always put DD's on our detectors that Rob the machines of depth and they suffer from EMI more, The only time you need a DD is when the Ground is too hot for the Concentrics

You have proved this to your self already with your Tejon, IE an 8" coil hitting coins at 12 inches, Remembering ??

That your 6x10 coil is equal to an 8" round DD 6 + 10 = 16 divide by 2 = 8 on depth and the average depth on that coil would be 8 inches, So if that coil was an 8 inch concentric that would bring you back to the Tejon's Depth of 12 inches,

If the ground is not hot then forget the DD's because you are loosing finds,

hope this helps,, john

[tvanwho]

Thanks John,

I can do some more experimenting without buying any new detectors for now..

Now on my Tesoro Lobo ST, I prefer the 3x7 coil, and it will hit metallic ores at almost a foot deep, like galena in Wisconsin,USA. Several times I got forearm size limestone rocks with a little hunk of galena in them with this coil at close to a foot in All Metal. My MXT I got before going to Ganes Creek, AK back in 2005, so it must be at least 11 years old and was used when I got it. The only gold nugget I got up there in Alaska was with my Lobo and that little 3x7 coil, however. It was an acorn size specimen at 5 inches, stuck in some bedrock fingers, just a whisper signal in All Metal. I wished I had used this combo my whole week up there instead of the MXT as I knew what to listen for and how to set up on the Lobo, was still a greenhorn on the MXT. And it was quite embarrassing when other guys asked how come I had just walked over a gold nugget they had found under my footprints? Happened to me several times. But we were told to dig only LOUD signals and ferget about the quiet signals I had trained myself to listen for on the Lobo......

Hmm, and the 8 inch concentric on my Lobo will hit mens gold rings at 12 inch ,no problem in All Metal, but barely 8 inch on coins. Guess I need to spend more time with both machines this year and take notes...

[auminesweeper]

Sometimes it is very easy to walk past a target even though you hear the beep mainly around lunch time or late in the day, I will take a break at mid morning and at lunch and then at mid afternoon, A sure sign that you are getting tired is when your swinging away and you start to gaze way ahead of your self because you only do it when you are not concentrating, for most of the time the MXT is a set and forget type machine but you have to up date the tracking now and then., when ever your mind starts to wonder that's the time to take a break.

 

 

john

[tvanwho]

Wise words John. I know I stop dredging/sluicing/highbanking for gold when I get up and trip over my own feet repeatedly. Its a sure fire sign of needing some R & R or time to go home and take a long nap. Wonder if this happens to other people too?

[auminesweeper]

Tom, I carry the Large Stanley Aladdin Flask when I head out and it hold about 2 Quarts, So I can Drink Coffee All Day and get up in the middle of the night for a comfort break, Lol

After a good cup of coffee I am raring to Go, It helps me to stay focussed even if I stop just for 15 minutes for lunch I'm good for another 5 or 6 hours,

I am ordering a few coils from whites tomorrow, because it is cold here and we are supposed to be getting snow soon ? so I might as well get out and do some testing,

john

[tvanwho]

Isn't it summer time down under? We got snow yesterday in Illinois. 2 more weeks of February and somebody somewhere gets a birthday on Feb 29 this year...