GPZ 19 inch coil signal response.

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GPZ 19 inch coil signal response.

Post  G.B. on Mon Jan 23, 2017 7:14 pm

Here is a video of the Signal Response of the GPZ 19 Coil.
I have also tested the 14 on this patch but didn't get round to videoing that test session but when l get time l will do a follow-up vid. But l can honestly say the 19 smashed the 14 for signal response.

I'm afraid l probably had the audio about 2 units too high as l wasn't sure how well the gopro would pick the sound up.

https://youtu.be/Os4ZbhBpB9E

Settings used were JP recomended settings with a few minor adjustments to suit the conditions.

Cheers

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Re: GPZ 19 inch coil signal response.

Post  davsgold on Mon Jan 23, 2017 7:29 pm

Thanks GB, I watched the video earlier this morning, I also put a link to the video in the 7000 section as I thought it pretty good. Thanks again for the effort.

cheers dave

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Re: GPZ 19 inch coil signal response.

Post  flyspecks on Mon Jan 23, 2017 8:29 pm

Well done greg, you put a bit of work into that one. Just a little suggestion , maybe have hobo doing the filming next time Q34 T06

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Mon Jan 23, 2017 10:04 pm

Right you are Flyspecks. I had a few issues with the video that day and when l uploaded to youtube l wasn't happy with the vid so didn't make it public and was going to go back and do it again using both coils. I was mucking around with the youtube settings the other night and must have unrestricted it by mistake so when l realised it was public and had a few views l thought l may as well leave it up there until l do the other vid.

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Mon Jan 23, 2017 10:41 pm

GB, please correct me if I'm wrong, but from my experience, coil speed needs to be very slow to get a good response, and due to the weight, this is a coil for careful scrutinization of an area that one suspects of hiding deeper gold, rather than a coil for general prospecting. What did your tests reveal in regard to large targets at depth? Have you tried the 19"coil on Coiltek's test site?

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Mon Jan 23, 2017 10:49 pm

Reg never tried Coiltech Site not sure where it is.

As far as swing speed goes the video shows the differences between swing speeds and the audio responses on the larger bit.  If l had been using earphoned and not standing so far away from the speaker on the larger bit l could have heard it alot higher above the ground than where l pulled up at.

I actually find it ok for general prospecting as long as l have room to swing. It's more about coil control.

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Tue Jan 24, 2017 12:03 am

When l test a coil the first thing l test is signal response and how it reacts to my style of detecting.

l have also found it balances easy, handles emi better than l expected. It handles normal timings alot better than the 14 for the area l detect. Handles sides of mullock, throwouts and gully walls better than the 14

In Normal hotrocks and clay pockets can be a pain

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Tue Jan 24, 2017 7:28 am

While testing the QED at the Coiltek test site at Lucknow lead yesterday, Wombat and I made an unexpected discovery. What we found will undoubtedly cause some controversy and speculation. Initially, I thought it best not to report, however in the interest of solving this mystery, here goes.
After testing the QED we ran the GPZ with 14"coil over the targets. The responses, although a little soft, were all 'dig me' signals. We then switched over to a 19" coil that I had borrowed for the day. Using recommended settings, and upping the volume a bit, as we were using WI FI, we repeated the previous test. Working from the smallest target first, (which some clown had sabotaged with a little bit of rusty steel) we proceeded through the test, which it must be said produced a better response to all targets until we got to the '5.5 oz @ 27". NOTHING! No response at all. We looked at each other in confusion. Swept the coil over the target again. Not a murmur. Zilch. We were gobsmacked.
Perhaps someone can enlighten us on why this has occurred, because it just doesn't seem to make sense. Could someone please try this test with a 19 " at the Coiltek site to see if our result was just some strange anomaly?

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Re: GPZ 19 inch coil signal response.

Post  Wombat on Tue Jan 24, 2017 7:49 am

Sorry Reg for butting in on your comment. The 5.5oz targget was down 22", not 27" as stated. But I will agree with what you are saying about target response. We thought that the 19" would pick up that target, with no problems. But nothing, hardly a sound. Definitely not a "Pull me up sound" anyway.  scratch  All the other detectors we tried did pick up that target OK after a bit of adjustment.
wombat Wink

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Tue Jan 24, 2017 9:23 am

Sorry Wombat, I was reading from your notes, and took the 2 for a 7. I see now how I made that mistake.

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Re: GPZ 19 inch coil signal response.

Post  kon61 on Tue Jan 24, 2017 10:04 am

Nah, no need to ponder over that 5.5 ouncer Reg, the answer is quite simple, it saw you's coming & quickly put on its skin. Shocked Q35 Just kidding here fellas. It is hard to understand why on those larger smoother bits of water/weather worn gold, give out such poor depth results & not just on the 19 inch coil. Something more than just surface area or density of nugget is involved here, for we've had far better depth results on smaller size slugs of gold (according to their size) than on far greater in size nuggets. I believe that the purity of gold content has something to do with this & not the size/type nugget. Maybe someone else here can enlighten us more on why it is so.

Cheers Kon. Q11

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Tue Jan 24, 2017 10:38 am

Kon, The 'nuggets' at the test site, are in fact lead facsimiles, and not gold at all. They are supposed to represent nuggets only. Whether the 19" coil would have recognized real gold or not is an unknown, but it certainly did not react to the lead.

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Tue Jan 24, 2017 12:50 pm

Reg/Wombat.

Just wondering what ground type mode/timings you  were running with the Zed. Smoothing of or on.  If using varius modes eg. Diff/HY Diff/GEN  Diff / Deep
 Norm/HY Norm/Gen  Norm/Deep did you ground balance each one at the start.

Are the targets at Coiltech test site in tubes with air around them or in solid ground. How long have they been buried.

I'm interested in the 5oz result it could also be due to what they call detection holes for certain size nuggets at certain depths. All detectors/coils have them maybe you have found one for the Zed.

Reg. What does the young bloke you sold your 19 to think of the coil.

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Re: GPZ 19 inch coil signal response.

Post  kon61 on Tue Jan 24, 2017 1:10 pm

Well that changes everything fellas. In reality, all or any detector/coil tests have to be on or over gold nuggets (regardless of the type of test being used).  Gold being an element has its own degree of electrical conductance. Substituting anything else for gold, during a conductivity test, will give you different results.

Cheers Kon. Q11

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Tue Jan 24, 2017 2:23 pm

G.B. Settings on the GPZ 19 were the recommended ones with no smoothing and perhaps the sensitivity up a little higher than Jonathan recommends. It was already balanced from the 14, but a quick check showed it to be balanced.
As for the method of the test site, I have no idea.
I have had no communication from the purchaser of my coil since he paid for it, so I have no idea of his impression.

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Re: GPZ 19 inch coil signal response.

Post  Vivace on Tue Jan 24, 2017 3:01 pm

Reg.  I also have had the same results as you with the 19" coil at the Coiltek site about 7 weeks ago.  I systematically worked through all settings, going back to Factory Default between changes, and no way could I hear the 5.5oz target, no problem with any of the other targets.  Understand the other targets had been there for quite a period of time, but the 5.5 had only just been buried by "Hermann".  Maybe if he reads this he could shed some light on how it was buried and what it is made of.  Vivace

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Re: GPZ 19 inch coil signal response.

Post  Qld Sandy on Tue Jan 24, 2017 5:00 pm

G.B. wrote:As far as swing speed goes the video shows the differences between swing speeds and the audio responses on the larger bit.  If l had been using earphoned and not standing so far away from the speaker on the larger bit l could have heard it alot higher above the ground than where l pulled up at.

It's interesting to note that the low and slow coil swing speed loses the big nugget as shown at 5.41, 8.21, 14.33, 17.29 and 20.42. Low and slow is touted as being the ants pants, something that I've had reservations about for a long time. A mono coil can be swung fairly briskly as it sharpens up the target response and makes it more obvious. It also applies, it seems, to the Super D coils.

There is a line between too fast and too slow, and too slow is being easily demonstrated in this video. The old trick of slowing down the coil speed over a suspect hot ground signal seems to have been flung out the window, and something we need to revisit and test going by this movie.
Cheers.

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Tue Jan 24, 2017 7:07 pm

Qld Sandy, you realize that this conflicts with all previous advice from your Minelab experts?

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Tue Jan 24, 2017 8:16 pm

What is too slow or too fast is up to the individuals interpretation when you are trying to describe it in words.

That's why l do extensive testing on coil response for each coil l own. Everytime l get a signal l always cross check it from different directions and using different swing speeds/settings ect. I find the ground dictates how you use the detecter in a given area.

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Re: GPZ 19 inch coil signal response.

Post  Reg Wilson on Tue Jan 24, 2017 8:39 pm

G.B. I must say, you are very thorough in your testing. I hope you get hold of a QED as I feel you would be the ideal person to test it. I am heading off for some long overdue hunting.

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Re: GPZ 19 inch coil signal response.

Post  Axtyr on Tue Jan 24, 2017 9:20 pm

Hi there.

When I was at the Coiltek test site prior to Christmas they had just put down the 5.5 oz piece. My 14" coil on the 7000 failed to pick it up in any gold mode or depth setting.

Maybe because it had just been put in the ground or not I don't know. Next time I am out there I will try it again.

Regards Axtyr.

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Re: GPZ 19 inch coil signal response.

Post  Hermann on Tue Jan 24, 2017 10:11 pm

About 2 months ago I drilled a hole in a 45 degree angle, then I let a fishing sinker down circa 20 x 40mm.  The real depth of this lead sinker was 22".  I just could hear it with my 5000 coupled to a 15" Evo coil  in fine gold.  I then stuffed the hole full with dirt again.  The sinker was 5.5oz, and it was buried at the Coilteck test site.

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Re: GPZ 19 inch coil signal response.

Post  Axtyr on Wed Jan 25, 2017 1:08 am

I'm going back to my original swing speed.

Axtyr.

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Re: GPZ 19 inch coil signal response.

Post  Vivace on Wed Jan 25, 2017 11:20 am

Thank you for your reply Hermann. I am bewildered as to why the 2oz at 20" is easily identified and the 5.5oz at 22 " is unheard. Up until Reg posted his result I had blamed my age and quality of hearing, but have decided it must be something else. Maybe an answer will,I hope, with time and other responses, be revealed. Vivace

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Re: GPZ 19 inch coil signal response.

Post  llanbric on Wed Jan 25, 2017 12:25 pm

Hermann wrote:About 2 months ago I drilled a hole in a 45 degree angle, then I let a fishing sinker down circa 20 x 40mm.  The real depth of this lead sinker was 22".  I just could hear it with my 5000 coupled to a 15" Evo coil  in fine gold.  I then stuffed the hole full with dirt again.  The sinker was 5.5oz, and it was buried at the Coilteck test site.  

So is the sinker (circa 20 x 40mm) at 45 degrees?  What profile is available to be detected?

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Re: GPZ 19 inch coil signal response.

Post  rc62burke on Wed Jan 25, 2017 2:32 pm

In the video it appears that on the outside of your coil sweep you raise the side of the coil creating the dish effect ????? if we have been told anything at all it is extremely important to keep a very controlled level swing !! why are you dishing your swing ??

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Thu Jan 26, 2017 1:07 am

rc62burke wrote:In the video it appears that on the outside of your coil sweep you raise the side of the coil creating the dish effect ????? if we have been told anything at all it is extremely important to keep a very controlled level swing !! why are you dishing your swing ??

Very observant and how right you are rc62burke and on my part in the vid my bad.  I have always maintained coil control is vital and no doubt it is something you bring to the attention of members of your local prospecting club so I'm glad we're on the same page there.

On the day I did the video I'd previously spent a bit over three hours testing the coil there split over a couple of days and so knew in advance what coil responses were going to be so not expecting any surprises I was probably a bit relaxed whilst doing the vid and at the same time a bit rushed.  While I was filming the video it was fairly hot for our standards up around the 40 degree mark. I'd already been detecting since sun up and decided to take a break until it cooled down a bit and thought I would quickly do a vid at the test patch before heading off elsewhere for an evening detect.

If I had more time and was less rushed I would have slowed down a bit and done it properly  but I say that there would only be a very minute difference in the signal response. Also I should add that if I was using my earphones and as opposed to be so far away from the speaker I would have been able to lift the coil higher again above the larger target and still heard it. But being so far from the speaker I actually stopped when I was having difficulty hearing it

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Re: GPZ 19 inch coil signal response.

Post  Martin R on Thu Jan 26, 2017 12:29 pm

Very as a training guide for whats slow and normal swing speed , even when you were dishing the coil over the target the machine had no issues picking it up
It was good to see what swing speed was to slow it is after all a motion detector and needs some degree of motion for it to function correctly your vid showed this perfectly and should be guide for all

Marty

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Re: GPZ 19 inch coil signal response.

Post  G.B. on Sat Jan 28, 2017 3:17 pm

Martin

I appreciate your comment but l'm not sure the vid is up to quality to be used as a training guide as l am a bloke that is just a casual detectorist so I'll leave it up to the experts to do the training vids.

Because when it comes down to it l have very little education in the science of detectors. I just listen to those like JP and others and then try to adjust things abit to suit me.

I do a lot of signal response testing on my coils but that is mainly to tune my ear in to various responses the other responses l actually discover whilst out detecting  and it is those responses that surprise me more and most of those iffy signals that turned out to be gold are very hard to replicate on a test bed.

The reason l did this video was to show why l have confidence in the GPZ 19 inch coil.

 However its a given that you will never get an identical response on a gold nugget or lead test nugget as they would have to be exactly identical and placed in exactly identical ground conditions.

What response one gives the other may not and vice versa.

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Re: GPZ 19 inch coil signal response.

Post  Martin R on Sat Jan 28, 2017 4:36 pm

The reason I said its a good instructional guide was because no one else had gone and done a Vid of the different setting side by side in the field
True, sounds and responses will change from day to day as in a different field, early on JP said Normal would give you max performance but due to our hot ground conditions would limit the use of Normal.
Maybe since the firmware and "Dust Iron" Ferrite ring and now the smoothness of the 19Z coil makes a compression test even more important in understanding just what the Z is capable of

One thing your vid showed very clearly, was the correct swing speed with the 19z coil even when not just over the ground in almost every test you did the target was still there and swinging over long grass now means you might not miss that much anymore

I'm also looking forward to JP's phone vid clip and I dare say some of what he finds are what you have showed us in your vid

Cheers Marty

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Re: GPZ 19 inch coil signal response.

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