Real test!

[ivconic]

Each one of us already had many occasions to perform various air and in soil tests so far.
Usually detectors are tested to show "depths" in air or in soil.
Some tests are done better and some are not.
Some tests are done fair and some not.
Usually the "manufacturer" of the detector tends to perform test which will show his "product" in best possible light.
Many of tests are done in fair manner, to show some benefits or drawbacks of chosen model.
Last couple of years we were eyewitness of many good and bad testings, mostly on Youtube.
I can name some video clips that i like most, but i wouldn't, because it is really not the point here.
The point is that majority of people mostly tends to achieve greater depths with their detectors.
Minority of the prospectors (including myself) are not focused that much on depths - but more likely on some other features which are much more important than plain depth.
Recovery speed is the one of the most important feature. So lately we can see many more testings that shows such feature at some models.
Probably the most comprehensive tests were done by Norfolk Wolf, and all were presented on many sites as well as on Youtube too.
Norfolk Wolf indeed done a good job, showing behavior of many models under the very same conditions. In the past i was ready to put some remarks on his testings, but now i understand that he done that in pretty fair manner.
After he did all the testings in front of the camera - many others also appeared to do the same or similar stuff.
Now....
most favorite thing to show was some iron near the coin, or some mineral, hotrock or similar also near the coin. (PAY ATTENTION ON THIS! It is not the same case when hotrock is close to coin or constrained few inches away!)
Few days ago i checked a bit different thing;
i dug a hole 30cm deep. At the bottom i put 2cm bronze coin and than returned all the soil over it. So coin was "burried".
I took several detectors and tried to detect that coin.
Most of the detectors really detected that coin. Some of the machines detected it barely, some other more easier, with louder and clear audio response.
I am proud to say that my latest IGSL detected it as a piece of cake! Also my old SMW2 detected it pretty easy.
I also checked with Musketeer XS and 18cm coil (TS800). Weak detection, coil must be almost pushed to soil... but still detected!
Ok... that test was done. What was achieved with such test? Nothing really!
BUT! Keep reading this!

Next thing i done - i removed first 15cm of soil from a hole. Than i put piece of hotrock in it and again returned the rest of soil back.

Pay attention on this! Hotrock is NOT just near the coin - it is 15cm over the coin and 15cm under the soil level, covered with soil too (buried).

So... i took first of the machines to test. NOTHING! NO DETECTION AT ALL! Second detector... NOTHING! Third detector .. NOTHING.... !

I took 8 various metal detectors and tried.... NOTHING! NO DETECTION AT ALL!
Next 2 days i took 3 more metal detectors from a friends (XP GMP, DFX, Tejon) ... NOTHING!!!!

.....

So.... folks.... what are we talking about here all the time? Depths? Mha,mha,mha!!!!
.....

But wait! There is a hope! Minelab GP3000 DID IT!!!! Nice and clear DETECTION!!! With or without that damn hotrock - same DETECTION!

VLF's are definitely very LIMITED!

I can only wander... God knows how many gold coins i've been skipped so far in last 23 years of me being the prospector!??
And most of those nice gold coins were "deep" barely 5-10cm in soil!
So....
We have to put the finger on our heads and start to think; are we gonna chase more (only) depths... or we gonna finally make some REAL WORKING VLF!?

[ivconic]

Just to be sure; read carefully what i wrote above! Hotrock IS NOT close to coin! It is constrained from a coin, in soil.
Because when hotrock is indeed close to coin (over or under the coin) - than all better detectors DO DETECT coin easily.
So please do not confuse and mix those two situations!

[PERTINAX]

For a long time VLF detector on the market did not appear anything revolutionary, but cosmetic surgery at least promote of the construction published 30 years ago. Although coins are still only found to a depth of 15 cm, no matter how much money has been paid for the detector. Obviously, this type of device has reached its maximum level with current technology. The solution can be found in trying to work on two or more frequency, digital signal processing, adding various filters etc..

The above test indicates a disadvantage of this type of device, that is, they can not penetrate the ferromagnetic object and detect the coin below. 3000 GP succeeds because it is the PI detector improved with MPS and DVT technology, developed for use in highly mineralized soil in search for gold nuggats. That is why it was successful in that test, this does not mean that this device can be guaranteed effectively to find coins in the European area. The VLF detectors are still effective because of better discrimination and sensitivity. The fact is that is very difficult to detect objects behind the mask as Ivconic noticed, but my goodness,there is so much misses because of snake like movement of the coil and its cone of radiation which is why simply never can cover the entire surface of the terrain. Even when a search is performed by several trackers with different devices one after another. Finding coins is a hobby and so are the detectors, a little more expensive toys, but lately more and more people have this hobby as the only source of livelihood.

Following several years of this and similar forums, I got the impression that eminent manufacturers deliberately limit the depth of the detector device to its 15-20 cm for some reason, maybe they are preserving the rich depth for people that can extract large sums of money for the purchase of some scanners etc. It is impossible that telecommunications last 20 years are so advanced (think only of mobile phones and GPS) and metal detectors that are related fields of electronics-small.

Ivconic perhaps suggests a solution by integrating PI and VLF detectors which would be unified strengths of each of them and reduce their individual weaknesses. I wish you much success, as well as others on this forum in an effort to make a beast of detector that will not leave anything behind and will be able to make by the average electronics for little money.Good luck.

[mikebg]

Hi Ivica,
I want to know if your hot rock is bad or not. Make AIR test with a ferrite rod and your hot rock. Adjust a VLF metal detector to eliminate (balance) the signal from a moving ferrite rod at distance 15 cm. Then test what response creates the movement of hot rock at such distance - positive, negative or none.

[ivconic]

Hi Ivica,
I want to know if your hot rock is bad or not. Make AIR test with a ferrite rod and your hot rock. Adjust a VLF metal detector to eliminate (balance) the signal from a moving ferrite rod at distance 15 cm. Then test what response creates the movement of hot rock at such distance - positive, negative or none.

It's the one i am keeping in my workshop for some time.
This one:

http://www.youtube.com/watch?v=_Zf3GsrSlDg

and here:

http://www.youtube.com/watch?v=7KGhjhYyVIs


When GEB adjusted to fully reject this hotrock - ferrite rod is still a bit detected.
So, when GEB adjusted to reject ferrite rod - this hotrock is also not detected. Answer is response=none.

[mikebg]

STRONGER COIN SHIELDING THAN HOT ROCK

Have someone tested coin shielding with large ferrite core instead hot rock?

[habitbraker]

TGSL doesnt detect coin together with ferrite rod. I dont know about ferrite core in your drawing

[taliesin]

question for you mike

Have someone tested coin shielding with large ferrite core instead hot rock?

what graphics software do you use for your illustrations ?

[mikebg]

what graphics software do you use for your illustrations ?

My operation system is Windows XP which contains the old drawing program Paint.
I open the program by clicking
Start > All Programs > Accessories > Paint
After drawing the first line or symbol in the future figure, I save the file in *.gif format and continue to work. The saving should be done before adding any text, because when Paint not knows the future format for saving, it will make the letters with colored rims.
For resampling and fine rotation, I open the file with "Irfan View" and after the job is made, I save the file again as *.gif format.

[Qiaozhi]

what graphics software do you use for your illustrations ?

My operation system is Windows XP which contains the old drawing program Paint.
I open the program by clicking
Start > All Programs > Accessories > Paint
After drawing the first line or symbol in the future figure, I save the file in *.gif format and continue to work. The saving should be done before adding any text, because when Paint not knows the future format for saving, it will make the letters with colored rims.
For resampling and fine rotation, I open the file with "Irfan View" and after the job is made, I save the file again as *.gif format.

Try using GIMP, which is a fully-featured graphics manipulation program ... and it's FREE (and much better than the Windoze Paint program).
http://www.gimp.org/

[ivconic]

Depends of a task you are targeting... sometimes Paint(brush) is quite enough.
But sometimes you will need something better.
Most of the time i am using Corel Photo Paint 9. Very best!
Usually i do prepare some simple "objects" in Paint(brush), shape them in Corel Photo Paint and finalize all in Corel Draw.
Sometimes i even use Sprint Layout to draw some precise primitives!
Also lately i am using sPlan 7.0 and Front Designer 3.0
I am to lazy to "design" new objects, so usually am mixing various software and take various elements from each one, to finally get desired document.
Maybe is better that way? For me is better for sure!
So... it's just personal choice and habits..

[ivconic]

Or... look here:

http://www.geotech1.com/forums/showt...004#post131004

[Melbeta]

Thats pretty good...

Or... look here:

http://www.geotech1.com/forums/showt...004#post131004

Okay, that is pretty good, pity it is not in a very SIMPLE software to use... Most schematic capture (drawing) software are not that simple to use...
Melbeta

[WM6]

Have someone tested coin shielding with large ferrite core instead hot rock?

Really hot rocks have magnetic response (natural or produced by MD impulse), so we need for test magneto-ceramic ferrite to simulate really hot rock. For your safety use strontium ferrite not barium ferrite. And uncoated / non-metalized.

[ivconic]

Really hot rocks have magnetic response (natural or produced by MD impulse), so we need for test magneto-ceramic ferrite to simulate really hot rock. For your safety use strontium ferrite not barium ferrite. And uncoated / non-metalized.

This is true. Hotrock from my video clips is having noticeable magnetic features. When i test it with some permanent magnet - it is attracted. I have now 2 different types of hotrocks. The one i showed few times on video clips... and another one with a bit stronger magnetic features than first one. Second one i just got. In next video clips i intend to test and show both. By now, preliminary, i tested them with coins. Usually coin is easy detected when is placed under first one, but barely ...or not detected at all when placed under the seconnd one. Also second one is stronger attracted to permanent magnet than first one...