Measuring PHASE SHIFT IN PI

[Mechanic]

Hi Qiaozhi
I design and built discrimination pi detector approximately seven years ago.
It had capability discriminate between Ferro and nonferrous metals.
If pi discrimination compare with vlf detectors , it was weaker than VLF .
Best regards.

What kind of ground conditions did you use it in? Highly mineralized, or just mild ground?

Cheers

[B^C]

Gday Tinkerer,

I have been trying to simulate your Pivot & the sine wave, if this is it i may have an explanation for it & can give the spice model for it, have a look at the pictures & see if it resembles what you find?

Opposite Polarity of signal inverts the pivot.

[aft_72005]

What kind of ground conditions did you use it in? Highly mineralized, or just mild ground?

Cheers

It had more false signal when use in minerals ground than mild ground.
Best regards.

[simonbaker]

This is very interesting thread but we need to include schematic with coils and where measurements we are talking about.

Cheers,

-SB

[Max]

Hi Max,

OK we will make a special environmentally friendly model for you.
We take this picture of the elephant, roll it up and stick it into coil.
Then we zap it with 66A current to generate a 666 Gauss B field intensity.
This should beat enough C_R_A_P out of the elephant to generate rainbow colored eddy currents.

Tinkerer

Hi,
I was serious... I heard of elephants that fart so much that a medium sized car can run for 40Km with 24hours production of "methane" there...

What a global warming! I swear that's true!

About the discriminating PI... uhm... seems like the holy grail... or something... I'm still waiting for the pulsedevil but I think will not see soon... just an impression.

Kind regards,
Max

[Max]

This is very interesting thread but we need to include schematic with coils and where measurements we are talking about.

Cheers,

-SB

Hi,
yes... that's common problem when talking about disc-PI things... people start to think they discovered some holy stuff then start claiming they have patented it... and that the production is running and the wonderful 1st fully discriminating PI will hit the market next month.

Then nothing. Nobody calls... and you don't know if it's cause of some hurricane or vampire why the hell the design is lost forever...

What to say... already seen on the screens!

Just remakes...

But where is a workable circuit for that ???

Just I say there are things that could measure (sometimes) the conductivity of target if a specific size is matched... but cause you don't know which is the actual size of the buried target (do you ?) before digging it... they are mostly unuseful to me , at least!

Kind regards,
Max

[Tinkerer]

Hi,
I was serious... I heard of elephants that fart so much that a medium sized car can run for 40Km with 24hours production of "methane" there...

What a global warming! I swear that's true!

About the discriminating PI... uhm... seems like the holy grail... or something... I'm still waiting for the pulsedevil but I think will not see soon... just an impression.

Kind regards,
Max

Hi Max,

I hope I did not offend you. Just trying to be funny. It is not easy. so much gets lost in translation specially with jokes.

The holy grail, the impossible dream, reach for the stars. These things do have some appeal.
I think a discriminating PI fits into this category.

All the best

Tinkerer

[Tinkerer]

This is very interesting thread but we need to include schematic with coils and where measurements we are talking about.

Cheers,

-SB

We will get there. It looks as if a lot of information and knowledge is coming together on the subject.
I am grateful for your feedback.

Tinkerer

[Tinkerer]

Gday Tinkerer,

I have been trying to simulate your Pivot & the sine wave, if this is it i may have an explanation for it & can give the spice model for it, have a look at the pictures & see if it resembles what you find?

Opposite Polarity of signal inverts the pivot.

Thanks B^C,

there is a good chance that you are right. I am going to post some scope pictures of it as soon as I get it ready, showing small and large targets of different metals and shapes.

Tinkerer

[Qiaozhi]

Thanks B^C,

there is a good chance that you are right. I am going to post some scope pictures of it as soon as I get it ready, showing small and large targets of different metals and shapes.

Tinkerer

Could you also do these tests at different distances from the coil?

[simonbaker]

We will get there. It looks as if a lot of information and knowledge is coming together on the subject.
I am grateful for your feedback.

Tinkerer

Ok - but this thread is derived from some other thread, so good to repeat the essential information, like what is basic circuit for tests, test points, idea we're discussing, what coils (single, double, balanced, etc). Just hard to follow otherwise.

Regards,

-SB

[B^C]

Gday Simon, yes like i mentioned in the other thread we need a test standard so we can all test the same things & confirm results.

Why don't we just start off with a circuit--say Gary's _Chemelec PI circuit or something, everybody can assemble it cheaply & were under way?

It is all very confusing when we all have different & varying circuits to test with.

Many heads are better than one, especially mine.

[Tinkerer]

Could you also do these tests at different distances from the coil?

I had a very tiring work day today, so I have to leave some questions unanswered.
It would be nice if somebody could coordinate and organize all the information that comes together here.
Here is a test sheet of some time ago.

Tinkerer

[B^C]

Tinkerer, is there another file format you can attach your findings with, can't open the files?
I couldn't open the last PDF for some reason either?
Thanks

[Altra]

Hello Tinker, SB and BC,

Great thread. As mentioned by robbi_h in the other thread resistive ground minerals on IB or normal PI are a problem. You may want to make up a jug of salt water for testing. This can be made by pouring a whole can of salt into about 2 liters of water. This will simulate a weak resistive ground mineral, you will have to deal with it the field or beach. It will show a signal between 1 - 5uS. after a voltage transition. Unfortunately its in your zone of interest 2.5uS. Keep it going.

Regards Mark