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How the sensitivity numbers reflect the ground conditions?CTX
Posted by: Ben Town
Date: October 13, 2017 01:32PM
For the CTX seems like I saw some info that gave how the sensativity numbers reflected the ground conditions?
Below a certain number the ground was considered bad and of coarse the higher numbers represented good ground conditions.
I’ve looked around and can’t find the info?
Thanks
BT

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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: Jason in Enid
Date: October 13, 2017 04:39PM
well, there's no hard and fast rule to this. Bad ground does cause the auto-sens setting to lower the level, but so can bad EMI in the area. The ground balancing feature has been explained by minelab staff as a "last resort" to hunt sites where the ground is too hot, but it doesnt mean you will get normal types of depth by using it. The explanation I saw was that unless your auto-sensitivity was consistently down in the single digits, then you should probably leave GB un-selected. This is probably where the breaking point comes from that your have heard.

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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: Champ Ferguson
Date: October 13, 2017 06:55PM
Like Jason said, it varies with the area's soil. Around here, I consider mid teens to be starting into the crappy ground. My sites mostly run upper teens to low 20s and I've seen it as low as 5. (and even tho I am a geologist, I still don't know what caused that).

I recommend using Auto+3 to read your ground and maybe scout around, then force Manual as hi as you can effectively hunt.



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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: sube
Date: October 13, 2017 07:16PM
Quote
Champ Ferguson
Like Jason said, it varies with the area's soil. Around here, I consider mid teens to be starting into the crappy ground. My sites mostly run upper teens to low 20s and I've seen it as low as 5. (and even tho I am a geologist, I still don't know what caused that).

I recommend using Auto+3 to read your ground and maybe scout around, then force Manual as hi as you can effectively hunt.

Champ when I hunt at a fairground my #s in auto +3 are at from 13 to 23 same ground it's the amount of targets plus the ground that changes them .
Rust nails bottle caps foil p-tabs and the ground.
Just my thoughts Betsy running hot at 24 auto all of a sudden Betsy go's to 10 she says I'm tired I got to slow down bad ground I can't keep up with all the targets so she drops sensitivity to reduce the work load oh no :sad: she says he's going for the manual button so you crank it up as long as you give her time she won't complain .

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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: Champ Ferguson
Date: October 13, 2017 08:39PM
Yeah, it could be targets raising hell with me there, sube. Its at a high school track complex, so the ground could be anything; scraped, fill, old landing area, or who knows. The ground was so bad and such a limited area (no chance of emi causing it btw), I didn't even bother with it. Just kinda put it on a metal list as one of those spots that no one has probably ever hunted and will go back to it when I just want an intellectual challenge sometime.



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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: "Carolina"
Date: October 14, 2017 07:17AM
What I have been taught, is in auto noise cancel, the numbers shown reflect low mineralization or high mineralization . Then based on these numbers it gives you direction on hunting in low trash, high trash, ferrous coin or ground coin depending on the mineralization. I run my sensitivity in auto +3. I believe sensitivity is more about EMI and noise cancel about mineralization.



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Edited 1 time(s). Last edit at 10/14/2017 07:20AM by "Carolina".

Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: Ben Town
Date: October 14, 2017 08:58AM
Quote
Champ Ferguson

I recommend using Auto+3 to read your ground and maybe scout around, then force Manual as hi as you can effectively hunt.

This is how I start out , if I’m in a relic field the ground in my area is good so I can crank the manual auto and the trashy sites I adjust down .
So basically I’ve got it, I think

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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: mrwilburino
Date: October 14, 2017 03:59PM
Quote
sube
Quote
Champ Ferguson
Like Jason said, it varies with the area's soil. Around here, I consider mid teens to be starting into the crappy ground. My sites mostly run upper teens to low 20s and I've seen it as low as 5. (and even tho I am a geologist, I still don't know what caused that).

I recommend using Auto+3 to read your ground and maybe scout around, then force Manual as hi as you can effectively hunt.

Champ when I hunt at a fairground my #s in auto +3 are at from 13 to 23 same ground it's the amount of targets plus the ground that changes them .
Rust nails bottle caps foil p-tabs and the ground.
Just my thoughts Betsy running hot at 24 auto all of a sudden Betsy go's to 10 she says I'm tired I got to slow down bad ground I can't keep up with all the targets so she drops sensitivity to reduce the work load oh no :sad: she says he's going for the manual button so you crank it up as long as you give her time she won't complain .

I've seen that with the CTX and other machines that use ground tracking. Sometimes it seems like the amount of iron targets in the ground may be causing the detector to react as if the mineralization level was higher, so it adjusts the gb and sensitivity accordingly. When that happens, I usually disengage the tracking and do an auto or manual gb, although I haven't tried that with the CTX yet.



Fisher Teknetics XP Minelab

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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: dewcon4414
Date: October 15, 2017 06:07AM
A while back i read Andys book and he recommended NOT turning GB on. So...... of course i had to try it in the SALT water. The auto digits were running 12...... when switched to GB auto went to 17. Heres what may happen........ it adjusts to the salt water and all that smaller gold that MIGHT register suddenly disappears because its so close to the salt setting. You think you are getting more depth...... but are you loosing more targets? Would it be kind of like a PI at 10Us vs one running at 22Us?

Dew



Xcal II, Blue Xcal 1000, Sov GT, Exp SE
Whatever you do in life, surround yourself with smart people who'll argue with you.... John Wooden.
D. Meeker

Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: sube
Date: October 15, 2017 10:53AM
Quote
dewcon4414
A while back i read Andys book and he recommended NOT turning GB on. So...... of course i had to try it in the SALT water. The auto digits were running 12...... when switched to GB auto went to 17. Here's what may happen........ it adjusts to the salt water and all that smaller gold that MIGHT register suddenly disappears because its so close to the salt setting. You think you are getting more depth...... but are you loosing more targets? Would it be kind of like a PI at 10Us vs one running at 22Us?

Dew
That would have been very telling if you would of tried a small earing post to see in fact what was going on .

Manual GB is to be used when your #s drop into the single digits with GC the #s fell because of high mineralization or to many targets rust nails bottle caps and so on . Now the reason I think you can't use auto and get higher sensitivity #s is there are to many signals targets and ground noise . So we set ground balance to 1 spot where were detecting which disc out all ground signals for that very spot. Move 2 feet and the ground signals changes now your not ground balance as well as you were where you set it the only time you notice the ground balance being off is when the detector starts to increase your threshold noise and you ground balance again .

So minelabs recommends GB with GC the reason being is what I said above if you move 2 feet and the ground signal changes GC which separates ground noise from coin signal , will separate the ground noise that you got 2 feet away from where you first GB there by giving a better signal. Now when you GB you disc out the ground noise of that spot add Gc you dics out more noise so with all that disc your going to loose depth that's why minelab recommends not using except for last resort .

Here's something that got my interest this year a whoa moment I was using the 6 inch coil in a trashy spot auto 23 +3 fast on is what I was running got a cluck that was reading 12.39 come and go . (cluck coin at edge of detection ) so I speed up my swing speed and get a perfect 12.39 tone I start to slow my sweep speed down and it starts clucking again slower yet and it turns to a iron grunt with a little cluck in there real slow and signal disappears . :confused: you can do the same thing on your table at home . So going to slow can hurt well if the processor can't keep up with all the data it's getting what's going on with the speed thing is it that when moving the coil faster that it's not seeing all the small signals or don't have time to process the small signals and only process larger signals like the coin . Then again same thing happens when doing it on your table with no other targets around . Now if we use -0- nail coin nail if we sweep this to fast we loose it only with a slower sweep will we see it .:confused:

Back in the day when I swung whites 5db and 6000s the faster you swung the better the depth and id thank God I was in ny 20s:smile: so what is going on here .(better depth and id) same for the ctx dose not matter with deep on either . A sweep speed of 4 seconds back and forth for the 6 inch coil is just about right if to many targets take smaller sweeps or sweep the same sweep many times to understand what each target is . Still have to go slow which means inching forward .So many things to check and do test on it never ends . sube



Edited 3 time(s). Last edit at 10/15/2017 11:15AM by sube.

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Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: dewcon4414
Date: October 19, 2017 05:37AM
The FILTERING systems on most machines will knock out more NOISE or weak targets the faster you swing..... which in a way will loose you depth because its picking up more targets closer to the surface. When you slow down you hear those snap crackle pops of less filtered minerals.... a lot of times rust. Larger coils really take in a LOT of soil too. Sensitivity plays a big roll in the digits reflected too...... crank it up and watch um change.



Xcal II, Blue Xcal 1000, Sov GT, Exp SE
Whatever you do in life, surround yourself with smart people who'll argue with you.... John Wooden.
D. Meeker

Re: How the sensitivity numbers reflect the ground conditions?CTX
Posted by: mcb613
Date: October 22, 2017 09:35PM
Brn, if you get a chance to attend Andy’s bootcamp, he covers this and other tips and tricks.
I think the number be said was 12 , that indicates bad ground. He offers settings to counteract bad ground.

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