depth comparison with detectors.

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depth comparison with detectors.

Post by Guest on Sun 01 Feb 2015, 8:14 am

I don't think I have seen too much evidence of depth comparison between machine yet.

sure the ATX picked up some gold that the GPX didn't see but the vast majority was nailed.

All the vids u generally see on the tube has a person simply digging a hole till they are rewarded for their effort, not too many if any show u swinging a 5k and then someone comes over with say a 3500 or a atx or whatever to see whether they can pick up the signal.

generally all we are interested in is the size of the coil and a couple of settings..
The only comparison I have seen is Woody and his mods--the befor and after but these are restricted to a house/lab environment. I never see him out in the paddock. Detector react differently inhouse compared when taken out bush.

Like Cooper tyres--sure u get around 80k ks in the city but up here in the Pilbara u r flat out getting 40k on the same set of tyres. When compared to say a Maxxis or Hero then they are all equal. The depth of the tread is 1 factor for what justifies the cost of the tyre.

So hopefully we will see some exact depth comparison between the 7k-5k-and say a 3500. I left out the 2300 coz it wont be in the ball park due to the size of the coil and I don't look for small gold.

So when JP gets the go ahead hopefully he will show us the comparisons and the settings that were used,,

we have already pinpointed a few patches that are now flogged to see how good the 40% recovery rate is going to be.
Come for a ride JP.


regards
oneday

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Re: depth comparison with detectors.

Post by mulgadansa on Sun 01 Feb 2015, 9:17 am

Very Happy


Last edited by mulgadansa on Mon 02 Feb 2015, 10:32 am; edited 1 time in total (Reason for editing : deleted - off topic)
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Re: depth comparison with detectors.

Post by Wedgetail on Sun 01 Feb 2015, 12:09 pm

Ray,

I agree wholeheartedly regarding the Maxxis and the Coopers. The latter "chipout" on the edges and end up knackered in short time. Coopers are crap in hard stony or rocky ground. I see 'em all the time around Leo and Laverton, usually fitted on a 4WD that's dressed up like a two-bob hooker on Freo wharf!

On the other hand, the Maxxis were the best tyres I've ever had on a 4WD, without a doubt. Hard as hell, can't wear the buggers out, quiet on the bitumen and had a lot less punctures. Even those that did pick up a spike were plugged and patched, some of which were on the shoulder in that "hmmmm" bit, and three of 'em are still in use a "bush spares - get ya outta the poo spares".

As for depth tests have you seen the excellent work done by two well respected operators in Kal? One of whom is a highly respected Doctor of Geological Sciences. It was the APLA mag last year and it was bloody brilliant. No bull*, highly scientific and good repeatability with standardised test methods. Quality stuff & highly recommended.

Wedgetail


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Re: depth comparison with detectors.

Post by pilbara snapper on Sun 01 Feb 2015, 12:53 pm

Doing depth comparison tests correctly is hard work and no matter what you do some smart ar*e will always say you were using the wrong settings blah blah etc.

I have only ever seen one performance test done correctly and the results were put on finders forum years back and that test was done by myself. I copped a bagging for using a buried nugget and and the test was to see if the 12v system on my 2200 actually did make the difference that was claimed by the manufacturer.

Minelab and others make these claims about better depth but never show us the test method ......did they use the same operator,did they use the same coil, was the voltage of the battery the same and........most important.......was the operator blinded to the test
All these and many more factors can change or put doubt on the test results that's why most people don't bother ......its to hard. You only have to look at the medical profession and see how they test treatments against each other, it takes years.

I can say,that when I lived in Karratha I used to follow my mate John who was a gun operater, he used a 4500, me a 2200, I would check his signals and found most I could not hear a dame thing ! Most of the targets were small gold so you would expect that.
I also did my own tests on undug targets using the 4500 against the 5000, at the time I found the 4500 to be a bit better however after some time I tried using JPs fine gold settings on the 5000 and found the 5000 to be better
These days I'm happy to show a newbie the settings I find best but most times they know better and end up changing them anyway
Regards snapper

pilbara snapper


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Re: depth comparison with detectors.

Post by Moneybox on Sun 01 Feb 2015, 4:39 pm

We've not spent enough time detecting to carry out an accurate test but I think you would have to have the two detectors working side by side in the field. It's no good doing a demo on a buried target. The results are totally different to those on a genuine unknown target in the bush. You'd have to check each target before it's dug out and most of the time it's not going to be gold anyway. You'd need a lot of spare time and patience as well.

We buried a variety of metal objects lead, brass, steel, aluminium and a couple with combined metals like a wheel weight. There are 16 items I think at varying depths from about 50mm to 600mm and have been in the ground now for about 8 months. There identification and position are noted down somewhere. I'm hoping it will give us a good test ground for each detector. Unfortunately it's in the sand in Capel so not as good as in ironized ground but the best we could do close to home. It was quite interesting to see the comparison between the ATX and the White's GMT when they were freshly buried. The White's gave a good crisp signal on everything except for a 1kg chunk of cast iron at 600mm but also gave a good variety of sounds to help identify the type of metal. The iron check worked but was not accurate on either machine. The ATX found everything a little too easily but showed off the value and accuracy of the pinpoint feature. We've not tried it since the ground has aged but we're due to go back with the SDC as well. It's such a long way from home, about 100m I think.

When we first got the ATX it couldn't detect a 0.2g nugget at 30mm that Ktown Swinger found with the 5000 on the Nichol River flats. Another Ktown local with a 5000 couldn't detect it either when it was out of the hole. Since we learned more about the machines we've used this same piece of gold to setup both the ATX and the GMT each time.

A reliable test could only be carried out by an unbiased operator (hard to find) with good knowledge on machine setup and operation.

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Re: depth comparison with detectors.

Post by Nightjar on Sun 01 Feb 2015, 5:04 pm

oneday wrote:All the vids u generally see on the tube has a person simply digging a hole till they are rewarded for their effort, not too many if any show u swinging a 5k and then someone comes over with say a 3500 or a atx or whatever to see whether they can pick up the signal.

regards
oneday

Agree Oneday, and there are many posts talking about "how deep," that's about the same as "how long is a bit of string?"
If every nugget was round you could rebury it and do true tests, however as we all know most nuggets/species are irregular shaped and how they lay in their natural state in the ground will effect the signal.
One example I experienced with the 4500 was digging a 12grammer about the diameter of a 10cent piece and approx 2mm thick. Was using a 20" round Nuggetfinder Mono and the signal was barely audible.
Only a 350mm dig and it was out of the ground. First thoughts a nugget this size at this depth should have been booming because naturally you would think it would have been laying horizontal.
Decided to do some tests. Laying flat in bottom of hole with a bit of dirt covering it the target was screaming, at 45° it was about the original signal, edge up the target was gone.
There has been much talk about the halo effect but also how the nugget is actually laying in the ground, and what mineralised ground is between the coil and the target.
So many combinations, once out of the ground, air tests are a waste of detecting time.




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Re: depth comparison with detectors.

Post by pilbara snapper on Sun 01 Feb 2015, 5:14 pm

My point is that airtests or pre buried targets are fine for testing as long as this is explained in the test results, that way those of us that understand detecting can see that the claims made may be no where near the truth
Regards snapper

pilbara snapper


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Re: depth comparison with detectors.

Post by Inhere on Sun 01 Feb 2015, 7:08 pm

Nothing equals original in ground testing, but the next best is holes at different depth in the side of a creek bank.
Air tests are a total waste with a PI.
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Re: depth comparison with detectors.

Post by Guest on Sun 01 Feb 2015, 7:18 pm

agree air tests are a waste of time however they do give an insight to whether a modification or a different setting works.

I have a few places up here to play around with and look out if the 7000 does what its suppose to do.
Bernies patch-ray patch-sing well-13oz patch-50k peg the list goes on.

Hopefully we will have a new video camera next week to keep a record.

regards
oneday

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Re: depth comparison with detectors.

Post by Wedgetail on Sun 01 Feb 2015, 8:04 pm

I reckon the most definitive testing was done by well known and experienced operators, Cranston Edwards and Prof. Bob Fagan in Kal,

The results were in an APLA newsletter mid-last year. Very good and probably the best I've read for any form of credibility, thoroughness and standardisation.

But, moving on, the term depth is misleading. It's often a case of how "bad" the ground is and whether the transmit and then the return signal can get through the mineralised background AT A GIVEN DEPTH AND A GIVEN BACKGROUND.

I dispute those that say that a "depth" test is to be done in benign ground. Depth always has to be considered vs the soil type. Try two detectors in easy soil and you'll get damn near the same result. But try giving the signal filtering electronics some hard work to do and you could see are far more relevant comparison, It's not always a test of how DEEP a detector can go, it's often more a case of HOW DOES IT HANDLE A SIGNAL IN BAD GROUND.

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Re: depth comparison with detectors.

Post by Alan WA on Sun 01 Feb 2015, 8:08 pm

A good way to find out how good or better a coil is is to walk round with one for a month then walk round with another for a month. At the end of that see which month produced the most weight.

I used to do that with new coils.

Probably not quite what the threads about but might be of interest as an observation on beeping.

Alan WA


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Re: depth comparison with detectors.

Post by pilbara snapper on Mon 02 Feb 2015, 6:35 am

It's very interesting that we all have our own thoughts on what is best when it comes to depth or performance testing of a detector, at the end of the day if your happy with your machine then that's all that matters.

Minelabs claim of 40% more depth on the new toy must be based on some kind of credible testing....but what?
You would have to think that Bruce Candy and his team are very smart people and would have extensive in lab and field testing before making any kind of statements about depth etc.
How many in field testers work for minelab and how do they test these new models before release?
I stuck to using my 2200 right up to the release of the 4500,I still have that 22 as a back up detector it still finds gold but I would always pick up a 4500 or 5000 simply because they are more enjoyable to use and can pick up those fly specs.

It would be nice if JP could give us some details of his testing guidelines !

pilbara snapper


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Re: depth comparison with detectors.

Post by Guest on Mon 02 Feb 2015, 7:07 am

Once JP is given the go ahead by Minelab i am sure he will explain further the desired attributes of the 7000.
There is a dealers conference in the USA this week so maybe next week or Mid March.

regards
oneday

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Re: depth comparison with detectors.

Post by K town swinger on Mon 02 Feb 2015, 7:24 am

Hey Ray are you heading over to the dealers conference mate?

K town swinger


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Re: depth comparison with detectors.

Post by Guest on Mon 02 Feb 2015, 7:27 am

nah --stuck in workshop--starts wed this week.

regards
oneday

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Re: depth comparison with detectors.

Post by Wedgetail on Mon 02 Feb 2015, 8:45 am

Maybe a better way of explaining "depth". Let's assume a 5 grammer is sitting at say 9 inches depth. There are two detectors to be tested on that undisturbed nugget. They are different machines or models.

One machine goes over the nugget and gets a "diggable" signal whilst the other hears nothing and passes right over the top of it.

Question - "Is the second machine worse than the first in depth capability?" Answer - probably not. It's more a question of the second machine not having the signal filtering that the first machine has".

They both sent a signal out to the nugget at the same depth, both induced an EM field on the nugget, but poor signal filtering causes the second machine to hear nothing unusual.

Depth? Or signal electronics?

This is where all those settings on 4500 and 5000s for "timings" are important to understand.

Wedgetail


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