Why do Minelabs go so deep?

[darth]

Has anybody had the change to work out why Minelab P.I detectors go deeper than the others? What is so special about the 3 short pulses and the one long pulse?

[fairdinkum]

I dunno Darth but the old square law E.I. depth = half the coil diameter of the coil, no longer applies, I found a coke can in highly mineralised hard ground at 600mm using the minelad 11" coil, and an old garret with a 10" coil didn't even know it was there.
those SD2200D are sure hard to beat.

[pml]

One possibility is the detection of large objects. Large objects decay at an exponentially slower rate. So if you take two quick samples then you'll be missing out on larger object. Don't want to miss out on the rare huge nugget.

Another possibility is iron discrimination. Iron decays at a much slower rate. So it can be very easy to discriminate iron from small to medium and even some large nuggets, but such discriminations will miss out on the huge nuggets. I believe it is easy to discriminate a piece of iron such as a nail next to typical nugget. The nugget gives off a quick decay. The iron slowly decays. I believe you can further improve your discrimination success rate by studying the irons decay spectrum, but that's getting into Microcontrollers and FFT functions.

Peace,
Paul

[robert]

Minelab


Simply, Minelab is the best !!!
Not only the PI's, just look the IB's....
The very best ever!

[ivconic]

yes

Yes i can agree with you 100%....

[Hush]

With a little help from my friends...

Hi to all you guys!

First I wish you good hunting and happy new year! Also wish to thanks
some people which make this site so good: Carl, Ivconic,Geo, Hawk 17966,
Qiaozhi, kt315.......
I discovered this place few months ago, oh what a wonderful world! So much scematics, brilliant ideas, what to say- just fantastic!
My experience in hunting and constucting isn't big like yours even I made
some PI detectors like:some Conrad (Ivconic put the scheme at thread of
XR 71), Twin loop treasure seeker( it isn't good detector, don't waste your
time and money on it) , Delta Pulse ( yes, the good one) and some others.
5,6 years my "best friend" was Fisher 1266, and 2 months ago ,bought
Minelab Musketeer Advantage with 10 inch coil.It is very good machine,with
exelent discrimination and very good deep, in my opinion much better then
F 1266.Now I have chance to buy Minelab Relic Hawk for 700 Euros and
need your advice, becose I've seen many of you have that machine and
offcourse very respect your opinion.If you will be so kind to write some words
about your experience in mineralized soil, how deep is it(some tests if it's
possible- I tried to find tests on internet, but nothing useful).The coil is
very big (15 inch!), is it uncomfortable, and is it possible to use coil from
Musketeer? Please answer on my questions, and if I buy it, I promise to
make tests like Carl done with few detectors , on different soil type- it isn't
interesting for you, but maybe for some others. Excuse me for my poor and
bad english.
Salute you!
P.S.
Pozdrav tragacima u Srbiji!

[Geo]

Hi Hush. Happy new year. Sorry but i can't help you. I haven't a Relic Hawk. Maybe Carl or Ivconic.
Wishes

[Hush]

Thanks a lot Geo anyway.
Greeting you!

[corsar]

Minelab are deeep!
A friend has GP3000, it goes deep. I have seen SD2200 too. It is also a good metal detector. I've heard that SD2200D and SD2200v2 are the same in the electronics, the difference is only in the look (and weight). I'm just curious what processor minelab uses in SD/GP. It should be 16 bit motorola i think, everyone knows that minelab delete the chips values and names for security reasons, does someone knows what do they use in the Gold Detectors?

[Unregistered]

Has anybody had the change to work out why Minelab P.I detectors go deeper than the others? What is so special about the 3 short pulses and the one long pulse?

in simple terms,the ground decays as 1/t where t= pulse length and a conductive target decays exponentially. Therefore by using two pulse lengths a conductive target will have the same time constant (independant of pulse length) whereas the ground TC is dependent on the pulse length. Hence the receive amplitude for a conductive target will be essentially the same in both sampling windows but different for the ferromagnetic ground response in each channel. This enables the ML to essentially eliminate the ferromagnetic ground response and to make certain that very few conductive targets slip through the electronic net.ML's method also depends on using an approximately exponentially rising coil current before pulse termination and hence requires low impedence,low inductance coils. For further info refer to Candy,s Australian patents, good luck!

[CDMakaKvM]

For Fairdinkum

Fairdinkum: Do you think a White's Sierra Madre with a 15" coil could find that same coke can? The Minelab you have is a Pulse Induction, correct?
Everyone seems to swear by Minelabs. Thanks in advance for info.

Don

[JC1]

My Humble Guess

My Humble Guess as to why Minelabs go so deep

is the following: The Australian Government funded

the reasearch and development of a minefield military

metaldetector for the detection of mines. Alot of money

and solid engineering went into this development and was

funded until sucess was met.

The commerical unit therefore benefits from this

research and is built similiar and therefore rugged,

with comformal coated boards, etc.

[wheelgunner4]

detector depth

Hello all!


TRY a Nautilus DMC11-b with 15 " coil if you want to see DEPTH!!!!!!!


REGARDS! ED