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Ground readings on the Terra 70
Posted by: bfodnes
Date: August 02, 2007 11:28AM
Hi

What is your ground readings and what performance do you get from the stock coil in the respective areas.

My ground is reading from 16-38, I have not been outside those numbers on any trip.

Performance is good. Just wanted to know what others experience. Maybe especially in goldfields cause i dont have them here.

Regards.

Bjorn

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Re: Ground readings on the Terra 70
Posted by: Digger
Date: August 02, 2007 12:38PM
I consider this to be moderately mineralized soil. Lots of old coal mines around here. But no gold. My X-70 GB numbers generally run from high 20's to mid 40's, depending on the site. Around here, I am able to get more depth out of concentric coils than a DD coil of equal proportions, at (or near) full sensitivity without chatter. I don't believe coins are so deep that they avoid my X-70. (This part of the world was only settled about 150 years ago). I encounter some masking problems with the coil sizes currently available. But depth is not an issue. HH Randy



You'll never know for sure......unless you dig it! HH "Digger"




After more than 46-years of detecting, and having owned dozens of different detectors, I've come to the conclusion that maintaining success in the field is largely dependent on three things..... choice of site, acquiring a proper skill set for the detector and the detector itself..... in that order. Research, practice and persistence. There are no substitutes.

Re: Ground readings on the Terra 70
Posted by: Mike Hillis
Date: August 02, 2007 02:53PM
My ground generally balances out somewhere between 12 and 6 on the Xterra 70 but the norm seems to be around 10 to 8. Sometimes I get lucky and find a site that drops down to a 12. The hottest ground I've used it on balanced at a 6. I have no doubt I could find some that would be worse without having to try very hard.

HH

Mike

Re: Ground readings on the Terra 70
Posted by: Carolina Phil
Date: August 02, 2007 06:02PM
My Minelab X-Terra 70 balances from 13 to 25 and goes so deep that I recently had to purchase a Predator Model 80D-Relic Pro spade from DeMarco Detector Sales. My Lesche hand digger can only get down to 9 1/2".

Minelab, George Lesche and Joseph DeMarco, Thank You!



Edited 1 time(s). Last edit at 08/02/2007 06:39PM by Carolina Phil.

Most areas I hunt around here
Posted by: Mike Bearden
Date: August 02, 2007 07:32PM
with the 70 are fairly tough for a LOT of detectors because the ground is littered with iron ore and deep red clay. The 70 does an admiral job with bad ground.
The lowest I've seen it GB was 4 but most of the time it's in the 8-14 range. Also took the 70 to the Alabama gold camp, it actually has some fairly tame ground where the GB never went below 6 and often ran in the high teens most of the time.
And YES the 70 will hit those very small pickers in prospecting mode even with the 7.5 coil. I'd forgotten to bring the 18.75 with me and was pleasantly surprised the 70 was that HOT on small gold at that frequency :)

Here's an example of how small the pickers are at this place, smaller than a grain of rice for the most part.

Good Hunting
Mike




Re: Most areas I hunt around here
Posted by: Steve in Idaho
Date: August 02, 2007 09:04PM
I have used my X 70 for gold and coins. I use the 7.5 DD coil and run in the prospecting mode with the iron mask at 1. I run the sens up to max most of the time and I am in ground that runs from 10 up to 32. 10 being in Alaska and 32 in the gold country where I live. I also have found small pieces of gold and I have found some deep silver that ID's right on the button. When I get a target, I switch mode to coin mode and it gives me an ID that I will dig or ignore. I always ground balance and then run with the auto track on. Most gold will run at +6 and up to 30 depending on the size. I had a 4.2 oz nugget that I ID ed for a friend that was 16" deep and it gave me a constant 30 reading. He had located it with an MXT with a 12" coil. The small gold will show a +6 to a 10. I was in a spot that the ground was 32 and it still ID ed the deep silver. A dollar would ID as a 46, the silver halves would go 44. and the silver quarters would go 42 or 44. In better soil the will always go 42. I dug on silver dollar that was 12" deep and the X 70 still ID ed it as a constant 46 any direction that I went over it. I have used a lot of different detectors and the X 70 is the best by far. Good Luck



Edited 1 time(s). Last edit at 08/03/2007 10:24AM by Steve in Idaho.

Thanks.
Posted by: bfodnes
Date: August 03, 2007 04:49PM
Thanks

No disapointments to read at all and that includes what must be very mineralised soil (4 and 6 GB ) GB wow.

Its comforting to know for others too I think.

Does anyone know what absolutely neutral soil reads if its out there somewhere. I ve read that someone had a reading around 60 but dont remember much of it.

Regards.

Bjorn

I don't know how close to neutral it is but I got a 24 in woodchips. :shrug:N/T
Posted by: Mike Hillis
Date: August 03, 2007 07:59PM

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I'm glad to hear others have dirt on the far end of the spectrumN/T
Posted by: Mike Hillis
Date: August 03, 2007 08:11PM

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Re: Thanks.
Posted by: Steve in Idaho
Date: August 04, 2007 09:41AM
I must be confused....I know that the soil in Alaska where I hunt gold is not very mineralized and it gives a reading of 10 to 12. The soil where I live is very mineralized and it gives readings from 26 to 39. So the lower readings should be low mineralized soil and the higher the reading should be high mineralized ground. Am I right? If not then please correct me.

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Re: Thanks.
Posted by: BarnacleBill
Date: August 04, 2007 10:56AM
The ground phase reading i.e. 6, 45, 72 has nothing to do with how mineralized the ground is. It is an indication of the type of ground, magnetic, conductive, or a combination of the two. There is a technique to make a relative measurement of not only how magnetic the ground is, but as to how conductive it is with the X70.

But at the end of the day there is even a simpler technique should you wish to compare notes. Assuming homogeneous ground (no hot rocks), how high can you run sensitivity without falsing. I suggest making comparisons using the 7.5khz standard 9 inch coil same mode, auto-noise cancel, auto-GB, and check in AM mode by bobbing the coil for spitting.

As an example, one person could have a ground reading of 15 and get chatter at Sens=28, while another with a reading of 15 get chatter at Sens=24.

On a personal basis much of what I see is freshwater sand in the 8 to 12 range. But the big league stuff are the cobble fields where each cobble is it's own little piece of ground. Many of the cobbles will deflect a compass needle 45deg, so it drives many machines crazy and wreaks havoc on correct ID for metered machines. Throw in a little black sand and yehaww! Machines that do well are the Fisher CZ's, Red Heat Tornado with DD coil, and X-Terras with DD coil.

But I do have a Mount Olympus of bad ground, a train station that no machine or coil combination has been able to crack, it's just a nightmare. But sadly I keep going back trying to find the key to unlock it.

HH
barnacleBill

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Excellent comment Bill.....
Posted by: Digger
Date: August 04, 2007 01:25PM
I added your post to the FAQFAQ index under the Ground Balance topic. Great explanation. Thanks. HH Randy



You'll never know for sure......unless you dig it! HH "Digger"




After more than 46-years of detecting, and having owned dozens of different detectors, I've come to the conclusion that maintaining success in the field is largely dependent on three things..... choice of site, acquiring a proper skill set for the detector and the detector itself..... in that order. Research, practice and persistence. There are no substitutes.

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:thumbup: :thumbup:
Posted by: Jackpine Savage
Date: August 04, 2007 02:45PM
Great post Bill and on target!

Tom

Re: Thanks.
Posted by: Steve in Idaho
Date: August 04, 2007 09:08PM
I have checked the soil with a super magnet and when the reading is low,very little iron will stick to the magnet. When the reading is high,the super magnet when put into the ground will come out like it has bristles on it. Usually completely covered with iron. I always run my sen. high, but when the iron content is high I start to get chatter and that is when I have to back it down. I run with the 7.5 kz DD coil most of the time in the prospect mode and switch to coin mode when I get a target to get an ID. It works well in high iron soil with little chatter. I have learned a lot from this forum for using my X 70 and keep the information coming.

GB question
Posted by: rogerwalco
Date: March 06, 2012 08:25PM
Hi all--

Totally new to detecting, but having a blast w/ my new 305.

GB question: we live along the shores of Bainbridge Island, off the coast of Seattle. While i'm not fully grokking how to ground balance the thing--it seems like 3 or so (on x-t 305) "feels" right. Does this seem approximately right for what y'all know about the Pacific NW area? Will let me know if i am performing the balancing correctly. I'm sometimes in the fields, sometimes near / around the sea shore.


Thanks to everyone for all the great info (randy, hunting by ear--especially useful..TY!)

Roger



Edited 1 time(s). Last edit at 03/06/2012 08:26PM by rogerwalco.

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