Stop building PI detectors!

[Tim]

Funfinder, please make it immune to ironstone and the worst mineralisation for Australian conditions. With black sand meter, adjustable ferrous/non-ferrous meter, and able to see sub-gram nuggets at depth, as I have no need of another relic finder for mild ground whatsoever. . Analog, thru-hole, with adjustable coil tuning as well thanks.

Then I will go and clean up what the Lamebin dills have left behind. They are drip-feeding their worshippers 19 inch coils for their latest abomination at $1300 each!!!!

[Nupi]

PI PI PI PI PI when I'm reading this forum!
Please stop it, you are doing yourself no favor with it!

PI's are slow like a snail, they have no useful groundbalance, can't detect cavity
and discriminating or even notch-filtering metal is still at a worse level!

I'm telling you this because of many years of treasure hunting expierence!

When I'm sweeping the coil its 5 times faster as it would be possible with any PI detector
but exactly such a high speed is needed to cover enough ground in a given amount of time!
And believe me, my search results are not just good, they represent find-records meanwhile!

Put here some fine induction balance detector schematic which even can find cavity
and built that one. With or without programmable micro-controller!

PI technology is antiquated and always will be! You can't just simply "flash" the whole area
with an extremely high electromagnetical field and expect good results!
The soil is no playground for radar-wave-reflection!

Let's see it as a bad habit or fashion of this forum being that highly concentrated
on PI detectors but its like an addiction which should stop because it leads to nothing good.

If I would be evil minded I wouldn't care and even would be glad because with those
homebrew PI detectors the risk is pretty low that others can catch away my own treasures
but 1st those who built them are not where I'm hunting and 2nd the reason of life is
to reach for the stars and not for the junk-yard!

And if you're nice I even will reveal to you the absolutely best coil design ever within
the next year or so! An ultralightweight coil which finds small stuff but also super deep!
Of course it will be induction balance for highest sensitivity and contrast factor results.

Sorry, but it was really time for a little warning about PI and those who built it naively.

Don't waste your time with PI if you can built with the same amount of time, money and
expenditure some double as good detector, one with reliable metal-discrimination, GEB,
long lasting batteries, reliability and great depth!

I repeat: Stop building PI detectors!


ps:
And don't get fooled by those overpriced Minelab detectors!
They might be OK for gold-nuggets and those who find enough of them but they use
much more complicated technology and therefore plays in a different liga than "DIY-PI".
And even with all those technology behind including high price they are not the best if
it comes to old antique or very deep stuff.

No, no, no, buddy.

Let them make pi pi pi and seek with it.
So cleaned the search fields for us and remain good targets behind.

For us, the real aficionados and diehard.
Long live the VLF / IB.

[rickb]

Originally Posted by Funfinder

PI technology is antiquated and always will be! You can't just simply "flash" the whole area
with an extremely high electromagnetical field and expect good results!
The soil is no playground for radar-wave-reflection!

Seriously, you think PI detectors work like radar? Really?

[Qiaozhi]

Originally Posted by Funfinder
Seriously, you think PI detectors work like radar? Really?

That's why he mainly posts in the Off Topic section, and not in the Tech Forum.

[Carl-NC]

Put here some fine induction balance detector schematic which even can find cavity
and built that one. With or without programmable micro-controller!

I'll throw in a vote for a new BFO design.

[rickb]

"That's why he mainly posts in the Off Topic section"

And that's where this thread belongs.

[homefire]

I didn't realize Treasure hunting was a Race ! Been detecting sense the the early 1970's. Maybe that's why I have not found any gold coins yet ?

[Tim]

I'll throw in a vote for a new BFO design.

Could anything worthwhile be achieved by a micro-controlled BFO? Just throwing it out there.....

[SVEN1]

BFO?
I found my first gold ring with a BFO when I was 14 years old.

[Tim]

I am still impressed with Talking Electronics(Colin Mitchells) circuit 8, a shunt-fed colpitts. The AM radio BFO I made with it (110kHz) can see an Oz 5c piece near as good as any detector. This circuit is definitely worthy of closer attention.

[Funfinder]

OK, lets go for one compromise:

PI has a right to exist if its used with large loops from at least 50cm upwards!
Because under such circumstance the searchers speed will be slower anyway.
But with a real coil and not with 10 weak lose windings in some plastic pipe!


Of course the real deal would be using the PI at least with some 1 meter coil!
Because the results are much better with 40 or 50cm induction balance coils.

It's clear that you will not stop here with the PI stuff but perhaps you should
use some little satellite dish for better radar wave reflection! And no coil at
all but some high frequency shortcut generator! With the timing of the pulses
you still get into trouble, no matter how fast micro controllers you're using.
There's not much time for getting alot information out of the feedback signal.
Only if you sweep the coil in slow motion - but this is no prob with an 1m coil.

[homefire]

Yep. Found my first Silver quarter with a BFO ten minutes after putting batteries in the thing. They Still have a Place. Year ? 1972.....

[ivconic]

Minelab GP3000 was proven as superior over XP Gold Max and White's Spectra on detecting small silver Roman coins.
I had it for several months.
On occasion i went with two friends on very mineralized site, also heavy infested with various trash.
XP and White's were completely deaf on almost all signals which i had with GP3000.
And those coins were pretty shallow, some 10-25cm in soil. But completely masked with mineralization and other trash.
At the end of a day i had 22 silver "Denarius" and 20-25 bronze coins. Other two guys both had 5-6 coins.
I remember few moments where i had loud and clear signal and i called other two guys to check those spots with their detectors.
They came and checked; not even a mum sound! Completely silent and deaf at those spots.
And than i dug silver coins at mentioned depths.
Is this enough illustrative?
PI detectors are superior in many situations, I/B are not even a close competition at such cases.
Most of the finds i had during the '90s were with PI detectors.
And majority of those were with smaller coils, not larger than 35cm diameter.
So... there is very sane reason to make and use PI detectors.

[daverave]

I would choose pulse induction any day over any other type of detector !!! they have the raw depth on the beach which gives people the chance to find deep gold items and coins which other detectors would never find !!!

[kt315]

PI's are slow like a snail, they have no useful groundbalance, can't detect cavity
and discriminating or even notch-filtering metal is still at a worse level!

Re: Pulsed IB-VLF Detector instead of PI-Detector.

Posted by: Dave Emery (---.sip.clt.bellsouth.net)
Date: March 3, 2005 07:13PM

Aziz,
Eric Foster made a true PI with a balanced searchcoil which could discriminate over twenty years ago. The problem is that the reactive component suffers from ground effect. Using filters such as a motion VLF will result in amajor reduction of depth over a regular PI. In short it has been done and may well prove to be a method for the future once the problems involved with such designs are solved. The dream is to find a reliable method of making a regular PI discriminate like a VLF using only a mono coil.
----------
Hi Dave, When you say "discriminate", do you mean determining if the target is ferrous or non-ferrous, or are you referring to distinguishing between different kinds of non-ferrous targets, such as zip-tabs and coins?
Allan
-----
Allan,
I am talking about a fully variable discrimination control such as the control found on a VLF. Maybe even a notch discriminate control to boot! The detector Eric made was ferrous / non ferrous only but it goes to show you how far ahead he has been for so long. He made that detector over twenty years ago!!!