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Fun Project
Posted by: Reg
Date: September 14, 2011 12:00PM
Fun with testing a PI:

A while back a guy wrote me and asked if he could build a simple device using a 5 gallon plastic bucket for checking potential depth of detection. He wanted something more portable and versatile than what he saw on a Utube video that would allow him to use local dirt instead. The design was simple, place a series of plastic pipes through the bucket at predetermined depths so one can make a quick depth test. He wanted to then fill the bucket with the local dirt he would get from the area where he was going to hunt so it would closer simulate what his hunting conditions would be like.

Actually, the idea sounded good to me, since it was easier than trying to hold a wooden ruler with one hand and move a target with the other or constantly bury and dig up different objects. Now, for fun, my recommendation was to build two identical buckets one to be filled with the dirt and one left with no dirt and compare the results, at least for the first time. I ask him to please send me the results of any tests he did. So far I haven't heard anything back.

Ok, people what should he see in terms of a difference of depth of detection of different targets when he compares the dirt filled and non filled bucket? I decided to not post what I feel will happen between the dirt filled bucket and the empty one since I think it would be fun if a few people decided to try this and let us know the results. Besides, if I do hear back than I know people are actually reading my posts. So, do you expect to see any difference between air and filled bucket test? Now, if we run this test and then take the same target and actually bury it and then test, will the results be the same?

What I forgot to mention when building this bucket tester is the metal handles should be removed to obtain the best results. I emailed the guy who sent the idea and he had already decided to use rope instead of the metal handles.

Now, those of you with lots of buckets and plastic pipe might want to build different buckets with the holes drilled a little differently to see if that makes a difference also. Spacing between holes depth wise could be anything between 2

Re: Fun Project
Posted by: togg77
Date: September 17, 2011 01:35PM
Hey Reg--great idea with the bucket. I saw a setup on Utube where a guy was using a box,but it probably held a cubic yd of dirt so the bucket is muuuuuch better.

Re: Fun Project
Posted by: Reg
Date: September 25, 2011 04:05AM
Ok, has anyone built this bucket idea and if so, what were the results? Remember to build two buckets and only fill one of them with dirt.

Now, I have attached a couple of pics of the buckets built Patrick that he used for his tests. What was strange was in his tests, the bucket filled with dirt seemed to allow deeper detection than a bucket that was empty. Patrick mentioned his dirt filled bucket actually contained , dirt, sand, gravel and small rocks. Patrick used different sizes of round lead shot as test targets.

Because this is not what I expected, I decided to build my own buckets and perform the same test. On my dirt filled bucket, I used only a dry clay based dirt with no rocks and got different results. Now, I used a variety of different targets including two different size nuggets, a silver dime, a tab off a pop can, a nickel, and a 22 slug. My tests when comparing depth of detection using the two buckets didn't display any significant depth differences. This is what I expected to have happen. Having run air and actual buried target tests before, I never saw any difference to speak of. So, once again, I will go through the procedure of burying targets and testing again. One should keep in mind that I also was careful when running the buried tests to make sure EMI was not part of the equation. One other test I will perform will be to moisten the clay based dirt and repeat the tests. Yes, there is a reason for this.

Now, getting to a different point, past discussions on the PI forum provided some interesting information and possible potential tests to see if certain conditions could enhance a target's response. Previous discussions discussed what could possibly have potential negative effects and what might provide positive enhancements. In other words, this bucket idea provides a great foundation to help determine what happens with a signal from a desired target when other non desirable objects are nearby. So, lots of interesting tests can be performed for those interested.

Fortunately, building this bucket test unit was quite simple. More importantly, it provides a simple fast means of making quick calibrated depth of detection measurements.

So, for those interested, this is a beneficial idea.


Re: Fun Project
Posted by: draco
Date: September 25, 2011 10:31AM
Hello, this is the video.


Used: Tesoro Euro Sabre, Minelab Excalibur, Goldscan 5.

Edited 1 time(s). Last edit at 09/25/2011 10:36AM by draco.

Re: Fun Project
Posted by: ivanll
Date: October 19, 2011 09:24PM
It looks like a fun project, so we'll give it a go.

I didn't have some hot material for a bucket so a stack of bricks will have to do.
TDI-Pro with 12"Mono will GB at 9, if you do not GB properly you will detect the bricks (an easy way to trick someone with tiny gold pickers)

Had a few people to try it out, last one is now an owner of a TDI-Pro Oz version.

To expand the fun, submerge the bricks in water.

Got a slightly deeper test tube in the back yard 14" deep and filled with water to eliminate air space, slide the test target to desired depth.

It have seen a lot of testing and opened a few minds especially to coil sweep speed and coil type, not to mention what happen when lifting the coil of the ground.

Black cover at the end, is over a 12" deep adjustable test tube straight down, also filled with water.

As Reg said "Fun Project".... but,............:wiggle: one got to participate to get the benefit.


Re: Fun Project
Posted by: Eric Foster
Date: October 21, 2011 05:18AM
Hi Ivanll,

Bricks are good to simulate iron mineralisation, but you really need the surface that you place the coil on to be about 10 times the coil area. This is because the magnetic field from the coil extends laterally way outside the coil. If the bricks (or soil) are much the same area as the coil, then the magnetic minerals will concentrate the field under the coil and you will get greater range than in air, in most cases. Much like a ferrite core will act when inserted into a small probe coil. When a coil is placed on mineralised ground, or on a test box with a large area of soil, the field will tend to spread laterally and the vertical range is reduced compared to an air test.


Re: Fun Project
Posted by: Reg
Date: October 24, 2011 08:13AM
Hi Eric,

Great to see you posting again and with great information. You answered one important issue with a fully understandable response.

Hope all is going will on your side of the pond and I hope you are enjoying retirement. Now, let me know if you write a book and when it is available because I will definitely buy a copy.


Re: Fun Project
Posted by: Eric Foster
Date: October 25, 2011 09:43AM
Hi Reg,

It is hard to retire when you have been in a career for 45 years that has been enjoyable and challenging. I am fixing up a smaller workshop in my new location so that I can continue investigating new ideas in PI detectors. So, I will still be posting from time to time and keeping a watch on other interesting developments.


Re: Fun Project
Posted by: Terrytorment
Date: October 25, 2011 04:49PM
Eric, that sounds like good news to me :cheers:
Waterproof PI, DD head with discrim, I have one please :-)

Re: Fun Project
Posted by: ivanll
Date: October 31, 2011 09:16PM
Thank you kindly for the advise.
I'll get some more bricks and do a little rearrangement.

Concentrating the field under the coil sounds interesting, like focusing a light source.


Re: Fun Project
Posted by: Reg
Date: November 10, 2011 09:10AM
Hi Eric,

Based upon what you stated, then building this project doesn't really show a person what to expect if the dirt in the bucket is there or not except to maybe focus the coil signal. So, the open bucket works basically as well if the primary goal is to simply test for interaction of objects or a means of a quick standardized test of targets for depth capability.

On the plus side, changing the type of soil will give a person a little more idea of the possible operation of the detector at the specific GB setting required over the soil. For really bad conditions such as basalt, a simple adjustment over a stand alone piece of basalt or maybe a red brick would suffice, though.

Basically, from what you say, it doesn't matter if the bucket is small or large. So, having a larger test bucket or box works for adjusting the GB, but not much else, except maybe focusing the signal a little as long as the test box or bucket is not much bigger than the coil. Instead for a more accurate overall buried test, I guess one might consider filling a swimming pool with different types of dirt. That is of course would work better if one has a bunch of swimming pools so they can fill each with a different dirt composition.

With all this said, I still like this bucket idea because it does allow for easy positioning of different types of targets at various distances from each other to see if there is any interaction. I think people who do build this project will learn more about what to expect, especially when there are different targets having various conductivities located at different depths.

Thanks again Eric for the information and clearing up a few things for those interested.


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