Ferrite ring

Even if the ring doesn't appear to be doing anything, you don't know what you could be missing.
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Thanks for that link mate
I haven`t been using the ring much because it didn`t appear to make any difference.
I`ll be using it more often now
dave

This has got me a bit curious as to whether it would be advantages to also use it when ground balancing previous machines, namely the GPX4500.

Even though the GPZ Detector coil technology has been designed to pick up gold & penetrate better through high mineralization/iron rich soils,little has changed.
Gold,because of its poorer electrical conductivity to that of iron,will always represent an issue towards its detectability.
It has been know from the days of VLF,not alone pulse,that the higher the degree of iron in soil,a blanket type affect,or imaginary type of force field so to speak occurs,which in turn tends to hamper/reduce the transmit/receive field of the detector coil,from achieving its maximum depth potential,over a positive target such that of gold.
We can believe what ever we like,but as for what we might be missing,in terms of signal response to targets lying beneath these iron rich soils,it certainly can't hurt,if we don't know for certain,of their presence & if within detector reach,in the first place?

Cheers Kon.

I think you hit the nail on the head there Kon.Trying to differentiate between highly conductive ground and a poor conductive target at depth with the current technology using a magnetic field will always be difficult.

alchemist wrote:Even if the ring doesn't appear to be doing anything, you don't know what you could be missing.
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You could reverse this and show why the ferrite bead or balun is needed in the first place....

Place one of those small nuggets on a sensitive part of the coil. Then pass a ferrite rod over the nugget and the nugget will respond even though it isn't moving relative to the coil.

And another simple test while you are at it....

Place the coil flat on the ground, then place a coin on the ground at a distance from the edge of the coil where it would give a signal if moving, and the coin will also respond if the ferrite rod is passed over it even though the coin is off to one side and isn't moving relative to the coil.

The same occurs when the coil contains excess metal and is passed over natural ferrites in rocks etc. Some third party coils don't pass this test and are very noisy on some ground. The noise is from excess metal in the coil, not from the ground.

If it makes you wonder if there is that much of a difference from soldered joints ect in coils , why was it never done for the older or the so called current spec coils we see today for the GPX machines  

Marty

The ferrite beads weren't needed in earlier model coils because they sampled the signal later after the signal from solder joints and wire size had already decayed. It becomes a real problem with the 5000 in "fine gold" because it samples much earlier, thus the note from Minelab in the 5000's box warning you that third party coils might not be made to the newer specs.

From my understanding,the slightly magnetic ferrite ring,we were given to ground balance over,does nothing more on the GPZ,than cancelling a section of ground we might encounter,that has similar or equivalent composition/effects to that of the ferrite ring itself. Ground that exceeds the composition/strength of the ferrite ring,will require a re-ground balancing of the detector coil.
By the way (like many of us had encountered earlier on,before the ferrite ring ("my precious" came into existence ),we were all finding some form of gold,just by ground balancing the GPZ (accordingly,as per instructions) to the immediate mineralized soil/ground conditions,we were going to swing over.
So the ferrite ring does play a small roll towards keeping the detector running a little smother/quieter when first ground balancing over lowly conductive mineralized ground,but is not the do all/cancel all type of noisy ground,found within the various types of gold fields.
Apart from whats being discussed above & how the amount of ferrite present in the soil can lead to the masking of gold nuggets,using current detector technology,gold itself,can and does contribute to its own masking by (a) the way it sits orientated in the ground (as compared to being picked up by the detector transmit/receive field) & (b) by its internal & surrounding ground composition.

Cheers Kon.

Alchemist
Thanks for the video link, appreciate it. Gives me a better understanding and the need to use it for best results.

Peter

Ferrites generally are not conductive, or minimally conductive. That's why they are used for choke or transformer cores, to avoid eddy currents.

What's happening there is you've created a magnetic shielding because ferrites have like 500x the magnetic permeability of air, so all the flux is going straight into the ferrite instead of cutting the nuggets and causing an eddy current which is detected by the detector, which is why you can't hear them on the vid.

It's an interesting concept to shield out unwanted metal within a coil that you bring up.

But balancing to the ferrite will not make a target contained within the ferrite detectable again, unless you exceed the saturation point of the ferrite itself with a strong enough mag field or if there are open holes in it like in the vid where flux can freely cut the conductor instead of being sinked into the permeable material.

So why in the video is a Double D coil on a GPX machine being used instead of the coil on the GPZ 7000 and the GPZ 7000

If it is the GPZ 7000 that needs the ferrite to help with ground balance then why use the older machine?

It was my understanding that the GPZ 7000 needs the ferrite to GB on in ground where there is NO ferrite persent not on ground where there is an abundance of ferrite present, if ferrite is present in the ground then the GPZ 7000 is happy to accept that.

Unlike previous detectors the GPZ 7000 has 2 types of things to GB, the "X" and a "G" balance, and one of these is the ferrite, and the detector doesn't care if it gets this from the ground or from and artificial source like the supplied ferrite ring. This is the way I understand it works, please correct me if that is not the case.

cheers dave

The video doesn't demonstrate in any way at all why the ferrite core is needed to GB the 7000, it only demonstrates why it is an advantage to use the ferrite beads inside a coil fitted to any machine, PI or otherwise, that is designed to detect small nuggets in mineralised ground.

Pretty much spot on Kon...I was using ferites slugs years ago in testing various machines....

Thanks for the comments Guys

I'm building a coil and had the 4500 handy and so used that.
I doubt earlier machines will benefit from using the ferrite.

The main reason for the vid as Robby pointed out was to show the essence of the patent, which was concerned more with currents generated in metal parts of the coil by the magnetic field emanating from the ground and not so much the detector.

Two slugs of solder sitting close to the edge of the coil will generate target like eddy currents as the coil is moved across highly magnetic ground, (especially bad with this type of coil)

What you say is true Kon, we were finding gold before the ring came along, and as far as I can understand it does only provide a calibration point, and as you point out Jasong using the ring to balance the 7k will not allow nuggets surrounded by ferrite concretions to suddenly be unmasked.

The reason why I tied the 7k to this was due to a test I did before the firmware update. I had been detecting for an hour or so not finding much when I located a few nuggets at the base of a gutter. I gridded that 4 square meter area from all directions passing the coil ever so slowly, and believed I had cleaned it up.
I wandered on up hill a bit and then had an idea, try ground balancing at the spot and check again. So I placed the ring on the ground near the patch and passed the coil over the ring and it didn't make much response to it at all, but going over the patch again produced a few more very deep nuggets.

I believe using the ring on the 7k will allow better target differentiation in ground having a minor masking effect.
The fact that all the nuggets found after using ferrite in the example above were among the deepest found may be evidence of this special property ferrite has to mess with magnetic fields being lessened by the use of tge ring.

The magnetic material composition of the ferrite ring, and the balun used in the video will be slightly different.

I guess the point is, I have seen first hand how the use of the ring has provided more gold, and the new firmware extends this effect, even though at first it didn't appear to make much difference.

To fully unmask some gold will take new tech, and the 7000 is another step in that direction, but fortunately not all the gold is hiding in tin boxes.

Perhaps Jasong your "hotpots" are rising pipes of iron rich minerals focusing the earths' magnetic field into a tight area.

When I get out of town again I'll have a play with some ferrites and see if the 7 is better at differentiating the gold from the iron dust.

Cheers.

kon61 wrote:Even though the GPZ Detector coil technology has been designed to pick up gold & penetrate better through high mineralization/iron rich soils,little has changed.
Gold,because of its poorer electrical conductivity to that of iron,will always represent an issue towards its detectability.
It has been know from the days of VLF,not alone pulse,that the higher the degree of iron in soil,a blanket type affect,or imaginary type of force field so to speak occurs,which in turn tends to hamper/reduce the transmit/receive field of the detector coil,from achieving its maximum depth potential,over a positive target such that of gold.
We can believe what ever we like,but as for what we might be missing,in terms of signal response to targets lying beneath these iron rich soils,it certainly can't hurt,if we don't know for certain,of their presence & if within detector reach,in the first place?

Cheers Kon.

HI Kon.
Gold is actually approx 4 time more electrically conductive than iron while silver is the best conductor.

Spot on & I'm glad you picked up on that one Adrian.Let me rephrase that part. Gold because of its poorer or weaker electromagnetic conductivity (as seen and translated by the detector coil receive end signal) will always represent an issue towards its detectability,as compared to a similar in size/shape piece of iron.
If we're going by the electrical conductivity scale of metals,one will also see that lead is a poorer conductor than what gold is,yet by placing a piece of lead similar in size & shape to that of a natural gold nugget,one will find that lead wins in both the sensitivity side,as well as being picked up by current pulse technology,at greater depth than a similar in size/shape gold piece.
Without getting to complicated here,it is more about the much larger/longer/stronger,electro/magnetic receive end signal,that iron tends to produce,as compared to the return signal,of a similar in size/shape piece of gold.

Cheers & a Merry Christmas to all.

Yes iron is so easily magnetised and being high elec resistance compared to gold, the induced Eddy currents flow for shorter time in the iron and that is why it is so difficult to seperate the iron signal from gold eddy current signals which altho weaker than the iron signal, flow for longer but by the time you have knocked out most of iron signal curve there is not much gold signal left to work with.

It is interesting that My Infinium gives a stronger sig on pure gold than for lead of similar size and wt........It is also interesting that I have a truck load of lead sinkers found with my Finny but not a lot of gold.......Also for those still using the Infinium for beach work. Set the Disc/Pulse delay at around 2 or three and you will get better response to Aussie one and two dollar coins. The tone will shift from a wishy washy high/low tone warble to a clear high/ low tone.

Santa is on his way and this will be our first Christmas in 20 years without our Kitty cats. They passed on several months ago. aged 15 & 21. and the rest of the family is buggering off down south and so Cecilia and I are home alone. Humbug and Poppycock! See if I care, We will enjoy the peace and quiet.

An ideal conductive target (such as a solid uniform ring) can be represented by a coil with a resistor across it. A typical natural gold nugget has voids and cracks that break the eddy current path so it behaves more like several coils with resistors in parallel.

The ideal conductive object has a time constant (TC) defined by its inductance (L) over its resistance (R), or L/R, and the shorter the TC then the faster the signal decays. In this example a solid gold ingot is close enough for our purpose to being "ideal" but a nugget composed of the same gold and of equal shape and weight is composed of many shorter TCs so its signal decays much faster than the ingot's signal.

A lead sinker is a poor conductor but it will usually have a longer TC than an equal size nugget because it has a uniform smooth surface and has less cracks and voids.

Some advocate using an aluminium block to simulate a natural gold nugget because aluminium is close to gold on a conductivity chart but the aluminium block has no cracks or voids to break the eddy current path and it has an almost perfect skin, which is where the initial currents are produced, therefore it is a very poor choice.

Iron is a poor conductor but its magnetic properties enhance the inductance, giving it a much longer TC and a larger signal for its size than an equal size nugget. The magnetic properties of iron increases the inductance for the same reason ferrite does with a choke or a detector coil or probe.

"Conductor" is a very inaccurate term that was adopted soon after discriminating VLF detectors appeared and was used to describe known man made objects, mainly USA coins. The discriminator in this case is saying "I think it is a silver coin but if it isn't a coin then I have no idea what the metal is".

A large solid nugget is classed as a good conductor but a small nugget cut from it is classed as a poor conductor so it is obvious that the term "conductor" in this case doesn't refer to the metal's position on a conductivity chart.