Earth to Dave Emery...you still with us? Pulse Devil updates...PLEASE!!!! n/t

[WM6]

Please explain your concerns so all can read them and judge for themselves if they have any foundation. Dave. * * *

Hi Dave, my concern is only to enjoy a joy through training English in conversation. Your English is pretty well and I can learn some new grammatical stuff. Thank you.

[NC-Dave]

PS instead of complicated reference burst timing, gated PLL is better solution, at least i reproduced machine that way. Best regard.[/quote]

Tepco, I think I owe you an apology. Your post seemed to be attacking me for not having my detectors ready. I have received a lot of negative posts from people who don't think.

I am really glad that you tried out the method in the patent. The timing can of course be done using a PLL but the timing method when properly designed is more accurate for discrimination. Did you get good depth with your version of the detector? If you email me at [email protected] I will tell you more about the method and some things to try.

Your English is very good. Where are you from? All the very best, Dave. * * *

[Sean_Goddard]

US 20090045813. Chance for this to work properly and produce performance like described, making new leap in metal detecting is about equal to the chance to be abducted by aliens, due to many reasons. Field tests will be most probably postponed to some undefined point in the future. This is how it will compete.

ROFLMAO!!

Nice one Tepco EXCEPT let me ask you this...What have YOU done in the way of metal detector development over the last four years. AFAICS NOT A LOT MATE ! AND How many patents for things like new modulation systems for broadcast systems? I DON'T mean this in a nasty way, I myself have come up with many ideas and not followed them through, so I'm one to talk But Dave on the other hand..

I've SEEN and HELD the Pulse Devil, when Dave came over here to the UK late 2010. I played with it at Blackhats house and let me tell you.. IT WORKS, and it works VERY well.

ALL the claims which Dave makes are true, and I'm not just saying this, I've USED the machine too, and frankly I was impressed (and I'M NOT easily impressed).

I've used a LOT of machine, having sold just about every type over the last 10 years or so, I've also pulled most of them apart too and let me tell you, 90% are overpriced poorly made toys.

I've sold ALL my machines (12 of them) in anticipation of my Pulse Devil arriving (early January) and I will NOT be buying ANY other model of machine after that.

To sum up, Dave's machine does the job, better than ANY other machine out there at present, and I've seen the schematics too so I KNOW HOW it does what it DOES. Dave's design is SO simple it's ridiculous, and adds a fair degree of support to my long time statement that most detector designers are RUBBISH at electronics in reality!

One thing even I will criticise Dave for are the constant delays, BUT Dave is a perfectionist, so much so that he is in danger of never getting the damn thing on the market. I've repeatedly told him to get the thing on into the shops, but I get constant phone calls of the "What do you think if THIS idea" type? It just gets better AND better and if you know what I know then you would be one of the faithful too.

I don't suffer fools, pretentious cretins or stupid know all's (Not pointed at you BTW). Dave is NONE of those in fact I'd go as far as to say, he is one of the few people who get my rarely given rating of "genius" (Ivconic, KT315, and Qiaozhi are another three and there are MANY more on this forum)!

[pelanj]

OK, lets say it will be deeper and better in discrimination than E-Trac. How about the price? Is there any estimate? If the price would be less than 1200 Eur, then I would be interested in buying one.

[Sean_Goddard]

Dave is talking about TWO models now, a switch on and go one for around £549 (MAYBE less) and a full "user can control everything" one which will be around £650. I was talking to him last night and he is also talking about a CUSTOMISED model with hand built aluminium engraved cases, modified circuitry for around the £850 mark.

These prices are NOT fixed, might be lower, might be a little higher, but I tell you one thing, whatever the Pd costs, it WILL be LOT less that anything ML make AND it will live up to the claims made for it, be lighter and more reliable!

[pelanj]

Well, if the machine is out before spring, I have one more candidate for upgrade

[Tepco]

ROFLMAO!!

Nice one Tepco EXCEPT let me ask you this...What have YOU done in the way of metal detector development over the last four years. AFAICS NOT A LOT MATE ! AND How many patents for things like new modulation systems for broadcast systems? I DON'T mean this in a nasty way, I myself have come up with many ideas and not followed them through, so I'm one to talk But Dave on the other hand..

I've SEEN and HELD the Pulse Devil, when Dave came over here to the UK late 2010. I played with it at Blackhats house and let me tell you.. IT WORKS, and it works VERY well.

ALL the claims which Dave makes are true, and I'm not just saying this, I've USED the machine too, and frankly I was impressed (and I'M NOT easily impressed).

I've used a LOT of machine, having sold just about every type over the last 10 years or so, I've also pulled most of them apart too and let me tell you, 90% are overpriced poorly made toys.

I've sold ALL my machines (12 of them) in anticipation of my Pulse Devil arriving (early January) and I will NOT be buying ANY other model of machine after that.

To sum up, Dave's machine does the job, better than ANY other machine out there at present, and I've seen the schematics too so I KNOW HOW it does what it DOES. Dave's design is SO simple it's ridiculous, and adds a fair degree of support to my long time statement that most detector designers are RUBBISH at electronics in reality!

On the break, man! You not only will never see any of my advance in detector technology, or at least if you do, you will not be able to sell it to anyone, just because i'm doing this just for sake of pure hobby, nothing else, and everything will go public, but this is last thing people here are interested for. Instead, many people are interested in new RPI detector concept, so my post will be bit more technically oriented in that direction and maybe interesting to someone.

This RPI idea, and related patent paperwork is among us for quite some time, apparently detector itself is still not. Some time ago i tried to replicate it based on US xxx. and find out some interesting facts. Keep in mind that i never intended to build complete and functional detector, just wanted to try method itself, just for pure curiosity. At the end, i abandoned it, continued whit some other concepts, but not because this one is non-working and/or fraud, just because it is too problematic to implement. Controversial, so to say. What i learned in the process is that following only patent data, one will not go too far whit this one, as expected (simply, lawyer's paperwork must include either black hole in it, or just nothing, usually goes that way). So, few issues i'm stumbled upon:

1. Coil itself. Due to detector operating mode, must be absolutely perfectly shielded to eliminate any capacitive coupling between TX and RX side. Nulling is not an issue, however even slightest imperfection in geometry and shielding will transfer some minute amount of energy in RX coil resonant circuit, producing residual signal that cannot be "nulled" Keep in mind, this must shield two coils good enough to prevent capacitive transfer after healthy few hundred volts flyback peak. I have some experience whit coil making and shielding, even in "critical" designs, but this one is royal mess really, probably most demanding coil so far for any machine. I don't have idea how someone can mass-produce this (i lost 3 days to make it at least nearly right), but for excuse why detector is still not available, just this one is good enough for me.

2.Timing, i mentioned it briefly. Original version is complex, i replaced it whit something more simple, gated PLL. In essence, loop is closed after ref. burst is generated, having something like 20 zero-crossings to resync, then opened, then integrator will hold charge until next sync, maintaining freq/phase stability. At least, that worked somehow, i never tried original, when properly done at least half dozen solutions can be used instead.

3.Ground effect, very important and critical one! In original patentwork, signal processing is textbook "second derivative" VLF, ground balanced like VLF. Except this cannot be done. Just GB will be even worst compared to standard VLF, this is why: Same thing preventing standard PI to operate at very small sample delays, few uS in ground, fast response of mineralization, in this implementation will inject significant signal into RX part. Since RX is resonant, waveform ringdown time is now dictated by Q factor of RX circuit, not target decay time, this residual signal will mask large portion of target response. I suspect that some sort of "delay" must be used, dumping RX coil or disconnecting C in timed manner after TX pulse to blank this part, but no word about this in patent, as expected. I also suspect that something else is used, say, target information present during TX time but carrying different information, or even raw PI signal from TX coil, also not mentioned in patent as expected. (so that part of waveform is not presented on image below, this is patented commercial project, i just messed whit it for fun). Anyway, without some "tricks", what is in patent can not beat White's Classic, put aside achieving what is claimed, and even then, using very complicated circuit design.

Since author and inventor of this method is also member of this forum, please don't ask me anything more about this, i'm not competent to comment, and don't expect from me to post anything like schematics or details, ask on right place. Considering the fact that author is older and more experienced in electronics than me, if he decides to hide something below the carpet, i will not be able to find it anyway. My only question is, how close i get on this?

PS. RPI operation in real world, considering some issues fixed, 100% discrimination, waveform after TX, recovered from some backup 3-4 y. ago. I like to see successful development and machine on the market as soon as possible.

[NC-Dave]

Tepco, It looks like you had some fun trying the method. The balance is not as critical as you say it is. I have used some pretty nasty coils using this method and they worked fine. The ground balance and the discrimination work in much the same way as a VLF detector. The trick was to know the timing when the ringing signal in the coil was due simply to the LC of the coil.

The method uses a very weak pulse which is applied to the receive coil well after the signals are measured. The ringing signal thus produced provides the reference. Your PLL method is one way to do this. It is also possible to use a microprocessor. As you accurately stated there are a number of ways to get the reference.

I obviously did not show all the methods as the idea was only to patent the major claims. My prototypes have very good depth. The tuned search coil allows for a very good rejection of 50 - 60Hz power line hum as well as other interfering signals. There are a few tricks which one has to learn before you get one of these detectors to an optimum design.

I have not had the luxury of time to do as much work on my detectors as I want to. Right now I am coming out with a PIB or Pulse Induction Balance detector. It has a full range VLF type discrimination control and the extreme depth of a PI. I will be in Europe this January with some detectors. I was about to go to England and France in September but I had an accident and broke my wrist so I could not go.

Where are you from? I am going to guess Bulgaria as this country has many excellent engineers like yourself who work on detectors. I am originally from England but I now live in North Carolina, USA. No Roman coins or hammered silver here!!!

All the very best, Dave. * * *

[WM6]

Where are you from? I am going to guess Bulgaria as this country has many excellent engineers like yourself who work on detectors. I

* * *

Don't forget Serbian engineers, Dave, not less excellent as Bulgarian.

[NC-Dave]

WM6 Yes many Serbian engineers are brilliant, Dave. * * *

[satdaveuk]

And english ones