Gold Results

[green]

Haven't visited the forum in awhile. Had a PM when I looked today. Including results from a past test changing delay time and sample time to balance ground signal(GEB on, GEB off). Think test was done with Rx(two 200mm round coils, figure eight)Tx(oval surrounding Rx)1A peak coil current. My detector isn't working so I can't repeat the test right now. Didn't test the 18 grain nugget. Didn't see a better way to answer the PM. I am also interested in how my detector compares. What detection distance should I expect?

The last time I tested the US nickel the results were a little better, don't know about the other targets.

[kt315]

sorry, very accurately have to ask about what detector and hoping thats not new advertizing from ML.

[kt315]

http://www.geotech1.com/forums/showt...on-depth/page8

[green]

sorry, very accurately have to ask about what detector and hoping thats not new advertizing from ML.

http://www.geotech1.com/forums/showt...845#post209845
A detector I've been working on for a long time now. Thought I had it about as good as I could get it when I read a reply in another forum about detecting a quarter at 24inches with a GPX4500. 13.5inches is a lot less than 24inches. What would I need to do with my detector to detect a quarter at 24inches?

Are there some charts somewhere that list detection distance for some targets to compare our home made detectors with?

[Qiaozhi]

http://www.geotech1.com/forums/showt...845#post209845
A detector I've been working on for a long time now. Thought I had it about as good as I could get it when I read a reply in another forum about detecting a quarter at 24inches with a GPX4500. 13.5inches is a lot less than 24inches. What would I need to do with my detector to detect a quarter at 24inches?

Are there some charts somewhere that list detection distance for some targets to compare our home made detectors with?

I'm afraid that someone seems to be exaggerating somewhat, if they think they can detect a quarter at 24 inches. With an over-amplified VLF in an air test (and very little EMI) you might possibly be able to achieve this, but it would be useless once you got it off the bench.

[Koala]

I'm afraid that someone seems to be exaggerating somewhat, if they think they can detect a quarter at 24 inches. With an over-amplified VLF in an air test (and very little EMI) you might possibly be able to achieve this, but it would be useless once you got it off the bench.

I remember being upset at seeing an IDX doing 55 cm yet mine was 35 cm.

by adjusting the RX capacitor I could get close but it was totally useless on a real field.

Back in the day were there were loads of different detectors on a rally (now everyone has a Deus or NOX) nobody was digging much past 12" on coin size targets. Same today except the detectors cost more.

[Koala]

I find it interesting watching "aussi gold hunters"

I know it semi fake. But those high end detectors are only going a few inches on quite large nuggets

[Skippy]

I've resisted commenting, seeing as I know little about PI's.
But there's several difficulties with your questions. No-one else has your sample nuggets to do tests with, so they can't say what 'depth' they get. No-one else has a figure-8 IB coil on their PI, I imagine, either, so you're wanting a comparison with a regular DD PI coil ? Or a mono-coil ?

If you're wanting depth comparisons, you're going to have to come up with some reproduceable test targets. Including some that mimic in a representative way some real nuggets, like your ones.
I think with the knowledge we have acquired recently on the various testing/modelling etc threads, and some trial-and-error, it should be possible to make 'dummy nuggets'. The main problem is the fact that you're the only one with the nuggets. Modelling nuggets is something to consider when we bring those threads back to life again.

One thing I'm puzzled by, though: If your coil has a figure-8 RX, then it will pick up very little EMI, and a much-reduced ground-signal ? So would you actually use the detectors 'ground balance' feature with such a coil ?

[green]

I've resisted commenting, seeing as I know little about PI's.
But there's several difficulties with your questions. No-one else has your sample nuggets to do tests with, so they can't say what 'depth' they get. No-one else has a figure-8 IB coil on their PI, I imagine, either, so you're wanting a comparison with a regular DD PI coil ? Or a mono-coil ?

If you're wanting depth comparisons, you're going to have to come up with some reproduceable test targets. Including some that mimic in a representative way some real nuggets, like your ones.
I think with the knowledge we have acquired recently on the various testing/modelling etc threads, and some trial-and-error, it should be possible to make 'dummy nuggets'. The main problem is the fact that you're the only one with the nuggets. Modelling nuggets is something to consider when we bring those threads back to life again.

One thing I'm puzzled by, though: If your coil has a figure-8 RX, then it will pick up very little EMI, and a much-reduced ground-signal ? So would you actually use the detectors 'ground balance' feature with such a coil ?

I agree with most if not all with what you are saying. I started the thread as an answer to a PM. PM asked about dimensions of my nuggets, other than a picture and weight I didn't know how to describe them. No way to compare nugget detection distance. We need some standard targets. I have some ideas for standard targets, what thread would be a good place for discussion?

If I remember right my figure eight coil is close to a mono coil the same size as one of the Rx coils. The figure eight Rx does reduce EMI, better S/N. It also reduces ground signal but I think the detector is unusable in my yard with GEB off. Other than playing with my detector in the yard I've never done any detecting so just novice thoughts.

For comparisons with a PI. Thinking of a chart similar to reply#1 for detection distance(add coil size and what else is needed)tester fills in what he can. Integrator out values would be nice. Need some standard targets that most could find.

I would be interested in a chart for VLF for detection distance comparison but from what I read air tests don't mean much. I'm thinking if ground is cancelled, detection distance is less effected with a PI.

[Koala]

a while back there was some tests done with small squares cut from an alloy can.

I tried this but getting the squares the right size wasn't easy. The difference in area of metal varies a lot even at just .5 mm out.

thought maybe cutting out with a hole punch would give more consistent results.

[waltr]

The alloy can metal has been discussed and found there are differences in the can's thickness which also effect return signal.
If the can pieces are spec'ed with size and weight maybe they can be standardized a bit closer.

Coins are very consistent but are not equivalent to gold nuggets.
Gold nuggets are harder to predict due to irregular shape, porosity and varying Gold content.

I do have Integrator output measurements from my HH PI detector comparing various objects and some measurements at various distances.
Very possible to take measurements at say three distances that can be plotted to extrapolate to greatest distance detected.
http://www.geotech1.com/forums/showt...ake-on-the-HH2

[Tibuck19]

I find it interesting watching "aussi gold hunters"

I know it semi fake. But those high end detectors are only going a few inches on quite large nuggets

I love that show ! those nuggets huh ! me want some!

[Koala]

The alloy can metal has been discussed and found there are differences in the can's thickness which also effect return signal.
If the can pieces are spec'ed with size and weight maybe they can be standardized a bit closer.

Coins are very consistent but are not equivalent to gold nuggets.
Gold nuggets are harder to predict due to irregular shape, porosity and varying Gold content.

I do have Integrator output measurements from my HH PI detector comparing various objects and some measurements at various distances.
Very possible to take measurements at say three distances that can be plotted to extrapolate to greatest distance detected.
http://www.geotech1.com/forums/showt...ake-on-the-HH2

there must be a surface mount component from a major manufacture that we can all buy. Not that I am in a nugget finding area.

[Andi68]

[green]

Some test data I did awhile back for my nuggets and some solid copper wire. Depending on nugget orientation, TC varied between 1.9 and 6.6usec. Wondering if a piece of solid copper wire AWG22 to AWG14(TC 1+ to 8usec) might make a good standard target. Maybe a piece 10 or 20mm long. Copper wire should be the same anywhere and available. Need to finish my detector to try, maybe someone could do some testing, detection distance.

Nuggets on edge have a shorter TC because targets were in center of coil. Depending on orientation, TC could be close or the same as flat centered when over coil edge.