What Are Timings?

[Steve Herschbach]

All you can stand to know about Minelab timings.....

 

[oldmancoyote1]

13 hours ago, Steve Herschbach said:

The bare basics of PI is the pulse delay. VLF is called Frequency Domain because it is frequency based. Pulse Induction is called Time Domain because it is time based. VLF

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Great bunch of posts Steve.  I've saved them.  It'll take at least the rest of winter to absorb it. Thanks

[Lead Detector]

It's just a theory, but I bet if you set your timing to pre 1849, it will be much easier to find big gold. ? If that doesn't pan out, then I recommend reading the information Steve Herschbach posted. 

[Valens Legacy]

14 hours ago, Steve Herschbach said:

The bare basics of PI is the pulse delay. VLF is called Frequency Domain because it is frequency based. Pulse Induction is called Time Domain because it is time based. VLF continuously transmits and receives at a given frequency or frequencies. PI transmits, pauses, then receives.

Steve  I really appreciate the amount of knowledge that you share freely with newbies like myself on these forums and I have saved this information so I can learn more about this hobby.

I look at it as though every time I come to this site I can learn something new even if I am not able to get out and detect right now. When I am able to get back to detecting I know that with the knowledge tha I learn from here it always makes me just a little bit better.

Thank you very much.

I still think that my explanation was very close to what you said. Just kidding about that.

[Geotech]

Just saw this thread, and then read the older thread with Brent Weaver's video. I disagree with Brent (and so does Minelab, apparently) and posted a response in the older thread. In any case, once you have a "hole-less" detector, the channel responses can be used to extract a conductivity VDI, as the E1500 apparently does (I don't have one so I'm speculating). But this does not necessarily give ferrous discrimination as ferrous eddy responses can mimic nonferrous eddy responses. Steel bottle caps, ferinstance. But I'm keen to learn more about what the E1500 can do.

[Steve Herschbach]

1 hour ago, Geotech said:

Just saw this thread, and then read the older thread with Brent Weaver's video. I disagree with Brent (and so does Minelab, apparently) and posted a response in the older thread. In any case, once you have a "hole-less" detector, the channel responses can be used to extract a conductivity VDI, as the E1500 apparently does (I don't have one so I'm speculating). But this does not necessarily give ferrous discrimination as ferrous eddy responses can mimic nonferrous eddy responses. Steel bottle caps, ferinstance. But I'm keen to learn more about what the E1500 can do.

Disagree how about what? Edit - found it.

On Algoforce I don't think anyone is claiming ferrous discrimination per se. Ferrous will overlap across the entire non-ferrous range, just like aluminum overlaps gold. So the key is basically statistical differences between target types in any given location, pretty much what we have already. But attaching a number to identically repeating similar targets is surely a step forward from where we were.

[Kostas 13]

has been around for many years Lorenz has two balance channels that work independently or both together also with a dd coil it has ferrous-non-ferrous discrimination as well as a numerical indication and with the large coils it has a conductivity indication of 0-99 ... as you can see the conductivity reading on the pulse detector is not something new that Algoforce has discovered...

[Doc]

Let me try to confuse the issue more.  Because I understand what is going on, but I always try to explain things the way my average customer can understand.  I may not use technically accurate words but they help my customers understand the basic concept.

So as has been explained, timings are nothing more than adjusting the length of the pulse.  Long pulses go deep and find larger gold.  These are strong pulses and so they are able to go deep.  However, remember, in metal detecting for every plus, there is a negative.  When that long pulse is on, and sends energy into the ground. and then turns off, the detector starts measuring the decay rate of that energy.  In other words, how fast does that energy go away?  The detector keeps a running average of this decay rate.  Now what affects this decay rate?  Well mineralization for one thing.  When you super charge the ground with a long pulse, it goes deeper, but that means there is a lot of mineralization that is subjected to that energy field.  So every pulse on pulse off produces a different decay rate, however the detector is looking at the running average and all of this is happening in milliseconds.

So the first swing let's say on a scale of 1 to 10 it has a decay rate of 1.2 then 1.3 then 1.2 then 1.1.  Now you pulse energy into the ground and a piece of metal is there, or gold, it holds on to that energy and changes that decay rate to let's say 4.2.  Instantaneously that drastic increase in decay rate above the running average is so dramatic the detector alerts the operator via a signal that there is a target in the ground.

Now what is the downside to a long pulse?  All that mineralization gets supersaturated and because the decay rate is longer with highly mineralized ground, it can mask very small gold.

So that is why there are short pulses.  Because they don't go as deep and do not energize so much mineralization.  So smaller gold increases that decay rate more easily above the running average and produces a target signal.

The first series of Pulse Induction machines Minelab came out with, the SD2000 SD2100 and SD2200 would rarely find sub gram pieces because there was no variation in pulse or energy.  So the ground became oversaturated and finding small gold just did not happen.

In the GP series Minelab made the first attempt to mitigate this oversaturation problem.  So the GP Extreme, GP3000 and GP3500 they introduced DUAL VOLTAGE technology.  The theory being that if they alternated full power pulse with partial power pulse the ground would not become so overly saturated.  And VIOLA, we started finding smaller gold.

Then with the GPX series they introduced the ability to change those pulses or soil timings.  I'm pretty sure they combined that with the dual voltage technology.

So that is how I try to explain what happens with these different iterations of the Minelab Pulse Induction machines.

Now the GPZ7000 is a totally different animal and perhaps someday I will try to explain that in layman's terms.  It is not a pulse induction machine, and yet it still measures decay rate.  How do you measure decay rate when there is no starting and ending event?  With Pulse Induction, the starting and ending event is pulse off pulse on.  The GPZ7000 energy is on all the time.  So what is the starting and ending event?  I will let you think on that one.

Doc