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Half Sine Metal Detector Technology - Hybrid Induction Balance / Pulse Induction Metal Detector

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I always have my ears perked up for something new in metal detectors and metal detecting technology. I’m not educated enough to really get deep into the technical side of it, but I have a general layman's knowledge of the subject.

A couple years ago Carl Moreland, the Engineering Manager for White's Electronics, was interviewed on a radio show. I tripped over a reference to the interview on another forum and checked it out. It is very long, and near the end Carl dropped a bombshell. At least I thought so, but it went unnoticed and uncommented on in the metal detecting online world. I thought about posting it on a forum back then but decided to wait and see what developed. Here is the applicable portion of the interview:

Relic Roundup Radio Show, January 17, 2012, Interview with Carl Moreland, Engineering Manager, White’s Electronics

Transcript beginning at 50:57 mark:

Carl Moreland - “I can mention one technology that we’re working on because the patent has already been published… or the application, not the patent hasn't gone through yet. We’re working on something called half sine technology, which has actually been around since the 1960’s in geophysical prospecting applications. This is where instead of transmitting a sinusoidal signal you actually just transmit half of the sine and you can do that at extremely high voltages and high ? rates and so on. It’s technically not pulse induction but it’s not VLF either and it is a time domain method. And with that we can get really good depth and we can even get target id information and do discrimination and so forth.”

Can you see why I perked up at that? I am still amazed it did not get any notice at the time. Nothing happened for a long time. Then I got this PM from Rick Kempf recently:

Sent 29 January 2014 - 09:04 AM

Was looking for info on my new SD 2100 this AM when I sort of fell down a rabbit hole of old forum posts and emerged reading Whites new patent. About the first thing I noticed was that you were cited in "prior art".

Here's what they cited: http://www.voy.com/76600/7/475.html

The patent is here: http://www.google.com/patents/US20110316541

Is this something you knew about? Just wondering.

Rick Kempf

I told Rick, yeah, heard about that. It was the patent finally being granted from the application Carl mentions in the interview. It was fun getting a mention in a patent though I think it was just the examiner studying up on the subject and finding my old post helpful in simplifying the subject.

For a long time the Holy Grail in metal detecting has been something that combines the target identification of an Induction Balance (IB or more commonly known as VLF) detector with depth of a Pulse Induction (PI) detector. There have been many promises and false starts over the years, and that was one reason I kept the radio interview mention quiet the last couple years. Frankly, I had half forgot about it until Rick brought the patent being granted to my attention. Notice the title:

Hybrid Induction Balance/Pulse Induction Metal Detector

A new hybrid metal detector combines induction balance and pulse induction technologies. Target signals are generated from a transmitted wave that has both induction balance and pulse current inducing characteristics and uses pertinent sampling of the receive data. Combining the two data sources provides eddy current target identification while excluding ground permeability and remanence obscuration.

Is it time to sing Hallelujah? Well, there is a big gap in between getting a patent and bringing a detector to market. Many patents get filed and you never even see something directly related to the patent. Maybe it looked good on paper but does not pan out well in reality for numerous reasons. So just because White's was granted this patent does not mean something is around the corner. However, they have been working on it for over two years already obviously. And it has been some time since White's put something new out. I do not count remakes of the MXT etc as new. So I think there is reason to be hopeful we may see something one of these days.

John Earle is one of the unsung heros in the industry. He had a hand in many of the best products at Compass Electronics before moving over to White's after Compass went under. To this day I have never used a VLF that goes any deeper than my old Compass Gold Scanner Pro. John was one of the brains involved in that, as well as the White's Goldmaster 3, regarded by many as being the pinnacle of the analog development of that model line. I was fortunate to have met John at the factory some years ago. He is listed as the inventor on the new patent. Half sine technology is also mentioned in an earlier patent filed by White's, again with John listed as inventor at http://www.freepatentsonline.com/7649356.pdf

Looks like serious stuff brewing. Bruce Candy of Minelab makes mention of half sine technology in a patent application at http://patents.com/us-20130154649.html which makes me wonder about the new "Super Gold Detector" he is working on. But it is this most recent patent by White's that seems to put the finest point on it. Maybe the Holy Grail of detecting is soon to be a reality. The fact it is White's certainly gives me more hope than what we have seen in the past.

Edit May 2015 - see also White's patent for Constant Current Metal Detector

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I've been puzzled by the seeming quiet from White's re: new detectors, particularly on the PI front.  Was the TDI it?  Modest developments of Eric Foster's design and then nothing?  For years?  Didn't seem consistent with their history or the engineering talent they have there.  Then Garrett and Minelab introduce a series of new detectors, and still nothing.

Not being any kind of insider, or close to the industry, I'd be the last to know - but there HAD to be something going on that we'd eventually see.  Maybe something that would bast owners of older White's VLF and PI machines off their death-grip on the old machines, and justify upgrading.  At least something to compete with the inevitable new machines as their competitors leveraged their particular technical advantages.  Those kind of advances don't come along very often, but we can hope.

Good as the latest from Garret, First Texas and Minelab sound, I'm waiting to see if they have enough cost/benefit to justify an upgrade - by someone who can, e.g. find better uses for the money than a shiny new GPX 5000, however superior it may be in some situations.  I'm sure not going to jump until I see what White's has to offer this generation (or if they plan to offer anything new at all).

These patents show that they've not been idle, and give me hope that mid-range (affordable) White's detectors may be in the offing that will justify an upgrade, since their competitors haven't gotten me to jump yet.

BTW, these detectors are described in analog terms, while digital detectors have been out for a good while now.  Particularly in the PI's, digital signal processing seems to have come late.  The way to REALLY combine the best of VLF and PI (frequency and time domain) detectors is with DSP.  You see it all over in radio, with most of many modern radios being DSP.  "Software Defined Radios" they are called.  When are we going to see "Software Defined Detectors", with all the flexibility and signal processing power that implies (and all the cost savings!)?


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Not to raise the dead but maybe they bought some of the NEVER_QUITE_READY pulse-devil design concepts...which at the time sounded like it would be the final answer to prospectors prayers...

Sooner or later someone will make these technologies work in the real world...I hope I can still swing a detector when that happens.


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  • 1 year later...

Well, we finally know what it is that Minelab was working on, and ZVT is not half sine technology. Rumor (sorry Chris) has it a new White's hybrid may be seen by year end? (Edit - note this post was in 2015) We will see.

Can you imagine having a PI that discriminated like a VLF? How much is something like that worth to people? Another 10K detector? I would be first in line.

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I would be second in line. As the years roll by my trash threshold gets smaller.

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Ray, I made the 10K thing up to illustrate the point of such a detector being desirable. I have no idea when or if such a detector will appear, or what it will cost.

On the other hand if I could get my hands on a PI that discriminated to full depth for 10K I estimate I could pay for it with gold found in less than two weeks at several locations I know of.

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  • 10 months later...

I have been keeping this patent and White's Constant Current patent in the back of my mind for two years now. It seems with White's on the move once again something may possibly see the light of day eventually. Or not. In any case I decided it was time to revive the two threads from the archives.


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