David Emery

With the NEW Fisher coming SOME DAY....... ive been doing a little reading up on David Emery and his Pulse Devil. Some interesting information on PIs, user controls, and Disc.

[patents.google.com]

[www.minelabmods.com]

[australianelectronicgoldprospectingforum.com]

Soooo what ever happened to this guy and his Pulse Devil? He sure talked a good game. How long do patients like his last? It seems he did some posting on Carl’s site who also had an interest in a disc PI he pitched to Whites. Will some of this Pulse Devil concept appear on the Fisher?



Edited 1 time(s). Last edit at 09/22/2019 04:10PM by dewcon4414.

Lots of talk, promotion, and some field testing. Then no delivery of a production model with a myriad of reasons for the delay.........and then radio silence.

It seems like I heard about this Detector for 20 years.

Dave Emery was trying to go it alone - do the whole platform development, test and debug the electronics, design and productionize the mechanical platform - the whole works. Aside from the fact that the Pulse Devil may or may not have worked as intended, the challenge was simply too great.

I have no knowledge whether Dave E tried to interest any established metal detector company to acquire his PD project, but in any event, none did.

As far as I can determine, Alexandre Tartar’s Manta development owes nothing to Dave E’s Pulse Devil. The Manta is essentially a refinement of the two channel PI concept which Eric Foster developed into the Goldscan series - which the TDI is the offspring of.

Alexandre posted info about the Manta on the Geotech forum of Carl Moreland (now Chief Engineer at First Texas). Carl has posted that that was his first notice of it and he followed up his interest in it. This ultimately led Tom Walsh, the CEO at FT to be impressed enough to acquire the project’s intellectual property and hire Alexandre and his team.

The problem of how hard it is to design a PI detector with a usable degree of discrimination while eliminating ground noise is one which has yet to be solved in a commercially available detector. Even the Fisher AQ (AKA AquaManta) - which isn’t for sale yet - only claims the ability to segregate fast decaying target signals - these are low conductors, including the vast majority of gold jewelry - from slow decaying signals which include ferrous targets - and (sadly) silver and 24kt gold.

Having said all that, folks aren’t giving up. Here’s a link to a thread on Carl’s Geotech forum where news of Dave E. appears as well as interesting dialogue of new ways of utilizing information from a pulsed transmission.

[www.geotech1.com]

Rick Kempf
Gold Canyon AZ- where there is no gold



Edited 1 time(s). Last edit at 09/22/2019 06:09PM by lytle78.

Dave E's project will never materialize. (Unfortunately).

Tom was it one of those ...... looks good on paper projects or FAKE NEWS where it wasnt possible? OR has the tech caught up with him ....making it not worth the effort or money? It seemed if he had been able to produce it ...... we might have gotten a jump forward and now might have been using PI instead of VLFs.

lytle78 Wrote:
-------------------------------------------------------
.....
> The problem of how hard it is to design a PI detec
> tor with a usable degree of discrimination .....

Durned them laws of physics after all !

I don’t know.....Carl once mentioned disc was the easy part.

dewcon4414 Wrote:
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> I don’t know.....Carl once mentioned disc was the
> easy part.

Not that goes to the full-depth range of the machine. By the time you implement disc, you are left with no-more-depth than a standard discriminator. So you gotta ask yourself: "Why bother then ?"

Tom, I so look forward to demonstrating to you how the Impulse AQ does it. Of course you and I need to wait till it hits the market. How are the hunting conditions at beaches your way at year’s end. No news, just ‘askin.

Rick Kempf
Gold Canyon AZ- where there is no gold

Tom......anytime a signal is processed you loose depth it seems. As far as why bother.... i dont need full disc, just like hunting with the Xcal in PP and doing reverse disc. Find a target first...... then use disc like a PPer. I may well have to take a scoop off on SOME really deep targets...... but i wont have to dig down 24" only to find a bobbie pin. If i can gain that kind of depth and NOT have to dig all the way to the target ..... to me thats still a big plus. If the Xcal would give me 4" more id stay with that machine and how it works in PP.

lytle78 Wrote:
-------------------------------------------------------
> Tom, I so look forward to demonstrating to you how
> the Impulse AQ does it. Of course you and I need
> to wait till it hits the market. How are the hunt
> ing conditions at beaches your way at year’s end.
> No news, just ‘askin.

The beaches in my part of CA have been lame for the past 2 winters now. No erosion to speak of. I'm sure that .... for just testing sakes .... there'd be some fluke random clad on the wet sand in Santa Cruz, in a pinch.

dewcon4414 Wrote:
-------------------------------------------------------
> Tom......anytime a signal is processed you loose d
> epth it seems.


Well of course that's a given, for all detectors. That has always been true, that the deepest fringe range of the detection will not be strong enough to trigger any sort of TID (conductive vs non-conductive). And then , sure, the user can elect to ignore, or can elect to investigate those fringe targets. That's true of any machine.

But when it comes to a discussion of pulse, I'm just saying that the notion that a user will avail himself of fabled pulse depth AND discriminate all at the same time, has some "gotchas" to it. By the time you've implemented disc. (highs vs lows), you're down to the same depth you'd get on various other normal beach machines (eg.: Sov, excal, CZ's, etc... ). Also : Very "squirrelly" to use. Well .... if it's anything like the TDI anyhow.

Tom ...... you are talking about using the pulse delay as a disc right? It appears this machine may do it a little better if its as quiet as they say in the water at 7uS. Which i find hard to believe. It is only using 2 tones i believe as well..... so the processing may not affect it nearly as much. It does lack however the ability to adjust the power to the coil...... which would have been a nice advantage...... batteries are changing a lot very fast.