WHITES DUAL FIELD COIL

[kt315]

other guys are not so idiotics botanists with big lens at nose you present of. a monocoil is huge advantage of PI because very simple in the realization. I do not see deep sense to make PI coil like VLF coil. either it will be balanced or not balanced. if you need VLF coil so do VLF design and do not dramatically hysterics here on mithycal ground noise. PI works and works very fine at any soil. if your PI does not work it is only your problem, not of all geotechers.

[Aziz]

Davor, you are understanding me!
But the other guys...
Aziz

[daverave]

with respect to the other guys on here i think kt315 is right in his thinking about coils...pulse detectors have survived for many years with only one coil...from what i can see eric fosters detectors were all mainly one coil and he is the leading expert on pulse technology so if dual field is so fantastic then why did not eric foster develop such a coil many years ago....as i said before i think its all about business and we all seem to fall into that trap of thinking that this latest innovation is the bee's knee's when in fact it may only make a little difference and costing mega bucks.

[Davor]

No guys, Aziz proposes a completely different thing. If Rx coil is physically separated from a Tx coil it picks far less ground noise, and it is somewhat different from balanced VLF designs.

[kt315]

Aziz, there are:
- single layer coil
-single layer Tesla coil
- basket coil in another variations
too much to learn by Daverave... the world does not end by only dual field, what really not dual field but splitted coil in 2 part. every can split a coil in 3...4...5... xxxx parts.
and so go out to one layer winding. Gary Chamelec had researched them many years ago and discribed on his site. but some people are blind, they needs to rediscovery a bicycle and America continent for themself.

[6666]

not required

[Aziz]

Why don't you guys use seperate large TX and a small RX coil (concentric co-planar configuration)?
It outperforms a dual field coil. It is also reducing ground noise. And you can use much larger TX coils (getting more detection depth). You pick up less EMI noise in the RX coil too.

Have a look at the coil comparison Excel file somewhere here in the forum. That's a rocket science and for free! No one has done such a coil analysis yet.

Aziz

[daverave]

Patent? The Fisher Impulse used a damping resistor across the inner coil.

I was unaware of the White's patent. Got a number?

I'm (almost) more interested in who claimed to have invented it for White's. White's has been ripped off by engineers in the past. White's may be a competitor now, but they are for me personally a former employer and are now a respected competitor, a company with whom we have friendly relations.

No need to PM me, please post the patent number here. This is Carl's forum, and he's White's chief engineer whom I don't believe had anything to do with this. For White's sake, I hope none of the old saboteur gang are still unreformed on the payroll. Let the chips fall where they may..........

--Dave J.

why so serious Dave J. we are all mainly experimenters on this forum...the dual field coil is no big deal....in fact im better off using my single coil 15 x12 as i get just as good proformance...i think in industry manufacturers just bring out some new innovation to compete with competitors...i really believe now that the whites dual field detector has been improved more by increased amplification than by this dual field coil...we are all learning on here...we are not in busin ess to make from what we do....so pls just chill out !!!!

[Dave J.]

That' s funny, it reads right on top of the Impulse from the early 1990's. I don't think Dan Geyer would have intentionally ripped Kenny off, so I'm supposing that Dan simply didn't know what the Impulse was.

--Dave J.

[kt315]

Patent? The Fisher Impulse used a damping resistor across the inner coil.

I was unaware of the White's patent. Got a number?

I'm (almost) more interested in who claimed to have invented it for White's. White's has been ripped off by engineers in the past. White's may be a competitor now, but they are for me personally a former employer and are now a respected competitor, a company with whom we have friendly relations.

No need to PM me, please post the patent number here. This is Carl's forum, and he's White's chief engineer whom I don't believe had anything to do with this. For White's sake, I hope none of the old saboteur gang are still unreformed on the payroll. Let the chips fall where they may..........

--Dave J.

seems you do not read all posting... it was sounded in daverave's thread on his double field (tm) for surf pi. i keeped hot on the traces it in my archive as US7994789B1_dual field.pdf. Carl... Carl will say nothing and silent as always if deal touchs whites deeply interests. will be better do not call Carl soul up now.
we did this coil earleirly whites many years ago. yes there is some advantage but nothing fantastic. dual field is only regular adwertizing. I VERY hope Whites will leave all trying to repatent Tesla coil!

[Jose]

Davereve
As you say the advantage of a double coil is little, compared to a monkey. with exception that the field is more even and improves the detection of small objects, but it is an improvement.
The enameled wire is not advisable because it increases the capacitance of the coil, making it less sensitive to gold.
Expesor if the wire is generous also influences that improves current in the coil.
The PCV if well designed and good quality, as well as the quality of the components influences the self-noise, which can mask the target signal.
Also influences the size of the coil, the shield, etc.. Etc..
All little influence individually, but in the end makes the difference and in my opinion, you have to be careful in everything, so that in the end, the performance of the MD, is decent.
Jose

[daverave]

i would like to make a dual field coil but ive been doing some experiments and compared with my 15 x 12 coil that ive already made and i cant really see much advantage...i can detect small gold 9ct thin section ring at around 12 inches with my 15 x 12 using 30 swg single coil....maybe im wrong but i think whites have got more depth using other ways like front & back end increased gain and maybe stranded coil wire...i think the small 6 inch inner coil has little to do wi th better proformance...im just not sure cause im limited in my experimenting as im using just enamelled copper wire.

[Dave J.]

wind coils separately. have to put a damping resistor to inner coil (according to the patent). as second dumping resistor has set at PCB, so no need to add this second resistor in a coil.

Patent? The Fisher Impulse used a damping resistor across the inner coil.

I was unaware of the White's patent. Got a number?

I'm (almost) more interested in who claimed to have invented it for White's. White's has been ripped off by engineers in the past. White's may be a competitor now, but they are for me personally a former employer and are now a respected competitor, a company with whom we have friendly relations.

No need to PM me, please post the patent number here. This is Carl's forum, and he's White's chief engineer whom I don't believe had anything to do with this. For White's sake, I hope none of the old saboteur gang are still unreformed on the payroll. Let the chips fall where they may..........

--Dave J.

[Jose]

Daverave
As someone said in the forum, my coil is fantasy, and it's true, I never had my hands on a dual coil. Only perform experiments and I'm satisfied with the results, compared to a single coil, the intensity of the source signal is more for small items in the dual coil.
I would try two or three twisted wire of 34 swg that you have.
Also place damping resistance in the smaller coil, that recommended in the patent, and it was necessary to my home coil.
Values between 2 and 5 khoms, works well.
Experiment and test with different values and compare the results, trying to improve.
Everything is a matter of experience and patience.
Jose

[daverave]

This is Rovs coil , as in my picture.

i appreciate your help to me in making my coil....i dont have multi strand wire...i have a reel of 34 swg copper wire...could i use several strands of this 34 swg wire...if so how many strands do you think i would need ???