Question: What is the pulse delay when the Garrett Infinium's Disc dial is set to zero?

[ivanll]

Nice to see that tiny targets can indeed be detected.

There are unsubstantiated claims of nuggets detected with the Infinium LS down to the size of 0.05 gram.

When hunting for small targets and tiny gold nuggets the coil sweep speed most be slow (as has been stated many times)
this is where "LS" stands for "Laboriously Slow"

There is a simple way of exercising the required slow coil sweep speed.
Place a golf ball on the pinpoint spot on the DD coil and sweep the coil. (now use a little imagination)

It's a simple matter of careful set-up and operating at 0 Disc.

 

[Smitty II]

Ivanll,

WOW!!! If detecting a .05 piece of gold with a PI machine can be verified, that has to be one giant leap for PI machines. The only way I can even imagine detecting a .05 gram flake of gold
with any PI machine is if it were hammered out flat and very thin like maybe .001 of an inch. You might get enough surface area to maybe detect it. At the present state of the PI technology, I feel there are design limitations that would prevent any of today's PI machines for detecting a .05 gram flake of gold under natural conditions. I have been wrong before and I might as well start out wrong in 2009 so if it can truly be done I would like to see and understand how it was done.

There are some real electronic engineering reasons why PI machines have trouble detecting very tiny gold nuggets or flakes. A good VLF gold machine operating at a reasonably high frequency (20 KHz and higher) can detect tiny flakes that weigh less than 1 grain (15.43 grains in a gram). If a PI detector truly did detect a .05 gram piece of gold it would be competing with some of the better VLF gold detectors on the market. The little flat .15 gram piece of gold that I found is equal to 2.3 grains. A .05 gram piece of gold is only .772 grains. I know that nothing is impossible but at the present state of the PI technology, as I know it, this just doesn't seem to fit very well. Of course I will say it again, I may be ignorant, as I am just an old retired engineer and I am NOT up on the cutting edge of this technology. It sure sounds exciting though and I do think that there is a lot of good things ahead for the PI detection technology in the future.

I like your method of forcing a person to slow down his sweep. That would sure do the job.

God Bless and HH in 2009

Smitty II

 

[parrott]

n/t

 

[ivanll]

The Minelab GP3500 is quite capable of detecting tiny gold smaller than 0.1 gram with a coil size at 16 to 18 inch.

The Minelab GPX 4500 is even more capable with an 18" coil attached in ground a VLF unit would test the sanity of the operator.

However it takes more than a good tool to do it, the operator in this case apply a high degree of concentration, and also well and truly passes the golf ball test.

 

[parrott]

Gosh everyone: Thank you all for your input. The question I asked
was about the pulse delay of the Infiniumat zero discrimination...
I have no reason to ask but curious.

(However, one of my detecting buddies has a 4000 and he has found some
nice gold with it... One is nice 4-ouncer he recovered at 9-inches deep).

I'm just trying to learn all I can about Pi's with ground balancing ability;
and I hoped to learn more about the pulse delay using the Infinium
as my point of reference. I have used an Infinium for about six years
and have found a few nice nuggets with it, as well as rings at the
beach... I have nothing negative to say about any PI-type or VLF-type.
I just try to learn all I can, so please post more about whatever you
know about Pi's; I will listen. So thanks everyone...

 

[ivanll]

A few places to look at in the pursuit of understanding PI detectors.

PI Terminology_posted on this forum by: Eric Foster_March 26 2000.

The book Modern Metal Detectors (First edition) by Charles L. Garrett. (there was some mentioning of this book on the p2p forum)

Understanding the PI metal detector Page1 and 2. By: Reg Sniff. (Find it under Articles at nuggetshooters.com)

The Infinium LS is in a class of its own, to only look at the pulse delay would do nothing but provide an incomplete and confusing picture.
There are said to be 96 different frequencies in every pulse emitted by the Infinium LS, that to have a relationship to the overall pulse structure.

One of the keys to set-up of the Infinium LS is to know the difference between.

1: the pulse operating frequency (terminology used in the Owners Manual)( also called the pps)

2: the 32 steps where the pulse operating frequency can be adjusted to. (starting from "0" position 730 pps max and diminishing with every step)

3: the 96 frequencies that makes up every pulse emitted. (the 96 frequencies are not adjustable by the user and have nothing to do with the 32 step pulse operating adjustment procedure)

 

[Eric Foster]

Hi Smitty,

There are no technical reasons why a PI can't approach the sensitivity of a VLF on small objects. I have designed PI detectors for industrial use that can detect a 1mm sphere of non-ferrous metal. For that you have to have a pulse delay of 1 - 1.5 microseconds. However, for gold and treasure hunting, that short a delay is virtually unuseable as you would get so much pickup from the ground. The shortest delay I have used on a beach is 5uS which was OK on the dry sand, but near the water I had to turn back to 10uS. In dry desert sand you would be OK, but if there is iron mineralisation then you would need a good ground balancing circuit, as the ground signal increases rapidly as the delay is shortened. Maybe a hyper sensitive PI will appear on the hobby market one day, but users will have to learn that only in certain limited environments can the shortest delays be used.

Eric.

 

[Bence]

Hi Smitty,
Many, many, many gold detectorists using GP's or GPX's will tell you that they have found nuggets under 0.05 grams. I myself have found 4 nuggets that didn't register on my digital scales, and as my scales round off to the nearest 0.1 gram, I have to assume that they were less than 0.05 grams. 3 of the nuggets were found with the 14" elip mono Ctk, and one was found with the 18" mono elip Ctk! Now that's a big coil to find such a small nugget, but the elip coils are sensitive at either ends (for some reason they're a little more better performing at the back end) at thei tips, which is how I found that nugget. The 14" elip will find 0.2 grammers at its centre no problems.

There were a number of other reasons how I found these nuggets, such as quiet ground, good coil technology, external speaker with inbuilt booster, and carefull listening. This was with a GP 3000. Lots of people will be able to tell you similar performances, just read the gold forums and you'll see.

This brings me to a bit of a point: why don't Garrett make boosters and more accessories, these will aid in finding smaller nuggets I'm sure.