Single Digit Auto Sens

[ryanchappell]

Any tips on settings for bad mineralization. I am not getting a lot of depth most of the time. Today I noticed that auto sensitivity was as low as 8 at this one site and 12-14 at another. This is around Red Mountain in Alabama. I did dig a dime at 6.5 inches once, but it turned out to be dated 1990. I found an antique silver broach and a 1916 wheat 2-3 inches deep on top of shallow bedrock. I usually run it with high trash, but try both settings on ground and deep. Threshold I run about 24, multi tones conductive. I did try goes4ever's TTF settings. I do noise cancel when I see the real low auto sens, and sometimes it will take me up to the teens, about 30% of the time. It is pretty hard to find a spot in AM that is clean enough for noise canceling. I go real slow and use the high trash setting and a coin pattern to see around nails and can slaw, I guess that is how I found the broach. I have tried setting manual sensitivity higher, and using auto sensitivity to take advantage of the ETrac's frequency optimization at -3-+3. It does occasionally get auto sens in the lower 20s.

I have the feeling that I am only finding stuff 4 inches deep and the silver is 6-24 inches deep. I am detecting 70-100 year old schools, parks, and sidewalk strips.

I only have 40 hours on the machine, it only took me two weeks. I would be interesting to use a pulse machine and dig everything deeper that 6-8 inches, but I heard the TDI only got 6 inches in some parts of Tennessee.

 

[sugar]

i am gob smacked at the figures you guys tell me your sensitivity runs at in the states in the uk ours usually starts at 19 and is soon at 25 to 27 and then i usually run plus 3 so getting some great depth but even i am after a little more and may switch to manual have you tried manual at all when you are out on the field use the four directional cursors bottom left hit left and right will move you in and out of auto manual sensitivity and up and down will alter your levels you know when you are in auto as you will have the round clock thing rotating try manual at say 15 if it seems too jumpy wind it back a bit and if it settles go up a notch its all about trial and error and ground conditions see how you go anymore questions just shoot happy hunting

 

[ryanchappell]

Yes, I have been experimenting with manual. I think it helped with the broach

 

[stasys]

use manual sens. and manual noise cancel, try different channels 1 is a bit different from 11. to make noise cancel you dont need clean spot because its related not to ground but to surroundings emi noises.

 

[NebTrac]

You're in a tough spot to say the least Ryan. I think your doing the right thing, and that is flip into manual and bump up until you get some chatter - then back off a bit. The sensitivity numbers you're seeing is what I would see when I hit cinder paths or behind a school where they unloaded coal into the chute.

Let us know how things are going.

NebTrac

 

[ryanchappell]

use manual sens. and manual noise cancel, try different channels 1 is a bit different from 11. to make noise cancel you dont need clean spot because its related not to ground but to surroundings emi noises.

Thanks sounds good. Will try.

You're in a tough spot to say the least Ryan. I think your doing the right thing, and that is flip into manual and bump up until you get some chatter - then back off a bit. The sensitivity numbers you're seeing is what I would see when I hit cinder paths or behind a school where they unloaded coal into the chute.

The cinder paths and coal trails sound a lot like the iron slag that underlies everything around here. They used it to pave paths in the parks and it is around the sidewalks downtown. There are Civil War era coke oven and coal mine ruins with abandon rail beds paved in the stuff. It looks like black porous lava rock that was made into a gravel, with stones averaging 1 by 2 inches.

Even when the auto sens is up around 20 I still don't think I am getting more than 5 inches. That 6.5 inch deep dime was in old black soil and my auto sens was around 24. Next time I am somewhere with that soil I will try cranking it way up, I bet it will payoff!

 

[moonshine]

im not sure if you know this or not, but you can easily toggle back and forth between manual and auto with the arrow buttons, and can raise and lower the manual sensitivity with them also. if the detector falls to 8 on auto its probably about as effective as Radio Shack's detectors. id put up with the chatter and just listen for high, repeatable tones.

 

[Ray-Mo.]

Not sure what you mean as noise canceling is suppose to be done in the air a foot or more from the ground and is for EMI noise not ground balance.Sometimes when auto runs so low you have to crank up manual sensitivity as high as you can and still remain somewhat stable to get more depth.

 

[reltolbert]

Ray-Mo,

Andy Sabisch told me to hold the coil on the ground to cancel. He said the instruction manual is wrong.

 

[ryanchappell]

I guess I was suspecting, but not sure, that it was doing both noise canceling and some type of more in depth ground balancing. By finding a clear area, I was erring on the side of caution. From reading Andy's book and the entire manual, this was a logical conclusion of mine, rather than fact and I don't think I had assumed anything or taken into practice anything that was really detrimental to my goals. It is only my 3rd week with the ETrac, so you guys are the teachers, and I am the student. I am not sure if the NC in a clear area and the idea of it doing GB at the same time was my inference or a something actually stated in the book.

Ray-Mo, Andy Sabisch told me to hold the coil on the ground to cancel. He said the instruction manual is wrong.

Wow.

This is great. We got an ETrac because we want something more, complicated or not, we are willing to figure it out, and adopt new methods to achieve results.

 

[reltolbert]

Page 95 of Andy's book 'The Minelab Explorer & E-Trac Handbook' states: "Users should perform a Noise Cancel whenever a change is made to the
Sensitivity setting, when changing search locations or even as you move from one part of a site to another as ground or external conditions may have
changed. This will ensure that the detector is always using the optimal set of frequencies based on ground conditions, electrical-magnetic interference
and the selected sensitivity setting."
That being said, it's not always easy to find a piece of ground that is metal free before you can do a noise cancel, so you do the best you can and remember
to keep your coil on the ground when you perform the Noise Cancel.