Doubt About Pi (pulse Induction)

[Joel - cacadordereliquia]

Hello everyone, I would like to know your experiences regarding PI devices because I noticed that there are many people here on the forum who use this technology.

We know that VLF detectors pick up shallower and have more discrimination to indicate ferrous or not. Uitlizam 2 coils one to send another to receive.

Now regarding the PI (Pulse Induction) they use a coil winding, have less interference in mineralized soil and go deeper.

They have an excellent depth range, but they have a problem: they don't have the ability to discriminate different types of metals?

Share your experience in finding gold, how these PI devices behave in mineralized soil in hot stones and iron from the earth. I have the Gold monster 1000 it discriminates everything, but in mineralized soil the device is over a lot.

[Steve Herschbach]

Well the way it normally works is you use a VLF until there is no more gold left. Then you go back to the same place with a PI and often find gold the VLF missed. Often more than the VLF found in the first place. The only exceptions would be locations with very small gold and no large gold, or extremely shallow deposits with no depth. A VLF can leave little for a PI in those cases. But in many locations a VLF is skimming the surface, leaving the bulk of the gold behind.

If the situation is reversed and a good PI cleans out an area, there is usually nothing left for a VLF but crumbs. Many professionals therefore dispense with the VLF entirely.

Honestly there is nothing to doubt about that. It’s the experience of many thousands of prospectors all over the world.

[GotAU?]

Hi Joel,

As Steve mentioned above, I have a perfect example of what a PI can do compared to a VLF in certain areas. I was at a  site where I once used a Gold Monster and then a 24k to detect it, but there were many black magnetite hot rocks of all sizes all over the place which really made it difficult to use the VLF machines. I  went back later with a 6000 and it worked very well over those same rocks, and I was able to hear and dig up some small gold where both VLF’s had been previously. It was all the noise from the hot rocks that made me quit and miss the nuggets previously as it was just too difficult to hear anything over the site with them.  

[RONS DETECTORS MINELAB]

1 hour ago, Joel - cacadordereliquia said:

They have an excellent depth range, but they have a problem: they don't have the ability to discriminate different types of metals?

The 6000 in primarily normal timing can have a distinctive sound on medium and larger sized metals such as double tones on long pieces of metal. Boot tacks also have a very common sound that is very repeatable, quite different from low conductor targets such as gold and lead. So although not a true discrimination feature, with time one can tell the difference on a lot of rubbish type target responses.

The best feature of pulse induction is not hearing all the ground mineralization VLF's hear that mask a lot of gold targets. And with PI sensitivity now down to .03 grams your getting the majority of the small stuff along with the big deeper stuff in one coil sweep.

I still use a VLF for disseminated gold in quartz where a PI fails or in low mineralized rubbish covered placer grounds though.

[oneguy]

IMO you really need both vlf and PI to cover all the bases.....

[Lanny]

Along with Oneguy and others, I love the one-two punch combination of a PI and a VLF, nothing better for the ground I hunt.

As for the benefits/operation of a PI, you've received some excellent responses that I'd agree with as well. In addition, they are great at handling many types of hot-rocks, some ironstone, and are better at ignoring some types of pyrite deposits that VLF's struggle with. However, they will not ignore all hot-rocks or all mineralization, but do a good job on the majority of troublesome minerals and mineralization.

You will also notice a weight difference between a VLF and a PI, as the PI is much heavier so harder to use on steep slopes, etc.

All the best,

Lanny

[Norvic]

Going back in gold detector evolution, when PI was introduced it was the biggest jump in gold finds over the VLFs I experienced. This size of jump has not been replicated since, although I experienced a smaller jump with the introduction of ZVT. I suspect this is the same for most gold detector users who have been in this game since the VLF was introduced.

[geof_junk]

         Most of the time it is not a matter of how deep a PI or VLF goes or how small a nugget it can see. It is more about the ground you are detecting. You have VLF experience so to get or beat a small nugget a PI can match or exceed a VLF with a change of coil even if has to be smaller than a VLF coil. For medium coin size target a PI coil the same size will exceed the VLF in depth by ¼ to a ½ in most cases. 

         The ground (location, mineralisation, depth, other rubbish targets (junk and hot rocks) and terrain will determine the best type of detector to use. As I mostly hunted for new patches in shallow ground in Victoria Aus. high mineral soils I found the Minlab SD series features were not worth changing from my VLF's it was not till I detected West Aus. gold fields that I changed to the Minlab GP series as the false hot rock signals there in 2003 onwards. So select a detector that suits the gold size in the location you will be in.

      By the way every new detector from some manufactures claim 20 to 50% more depth than the previous model but beware the are not using the same target as the previous model best size target. So it's a different ball game, but in a worked out spot/patch it may find nuggets that previous model was not good at.   

[phrunt]

27 minutes ago, geof_junk said:

         Most of the time it is not a matter of how deep a PI or VLF goes or how small a nugget it can see. It is more about the ground you are detecting.

Common sense wins in the end Geof  🙂

 

[Joel - cacadordereliquia]

Thank you all for your sincerity and for helping me clear this doubt.

Now I know why prospectors use two different devices, one is looking for fine gold, the other for deeper gold.

This IP machine is quite expensive, but according to the report it is worth every penny, not to mention that the largest nuggets in the world were found with an IP device.

It already happened to me once where I was detecting a lot of hot stone and iron, the device kept beeping for everything when it was on the side, even lowering the sensitivity. That's where I ended up leaving the place and going to a place that doesn't have much mineralization, maybe if I had a PI I would have worked without being bothered.

I hope one day I buy at least a GPX 5000 to feel the thrill.