Coil Technology

Current coil technology to me is stale, we live in the world of advanced technology yet our detector coils have not moved on with the rest of the technology.
Same old coils in a new case, with very little difference from the old terracotta jobs to today's colorful replacements.
The old jobbies still work on our latest and greatest wands with very little difference between the newer ones.

I think its time the old wire wound coils were replaced with circuit board replacements.
Imagine a coil with serious circuitry where the coils windings are replaced with printed ones coupled to some fancy chips and all that other stuff you find in a clock radio thats served its purpose and is now disabled for its components as you do.

There's bound to be someone who says it can't be done, but before you embarrass yourself by saying this.....laser eye surgery has been out for yrs.... wrist watches with built in GPS and UHF radios were mythical gadgets when many of us were kids.
The list go's on and on with things we now use on a daily basis that were only figments of our imagination not that long ago.

So why is it that our coils still appear like frizbies from the 70s with the same technology.?
New casings, new mounts, new wire ,new shielding = only a poofteenth in performance, yet they still develop touch sensitivity like those of yester year.???

They say that the PI platform has reached its peak, so why not focus this peak into the ground where we want it with new coil platforms that take the PI to the next level.?

Time to move on coil manufactures, its the year 2012 .... and as of yesterday iv gotten older.

Great post Narrawa.We can use 10 year old coils on our new machines. Now imagine how a 10 year old computer compares with today's computers.
Unfortunately it's about demand and market size. As much as we love it, "Detecting" numbers Australia wide are small. Therefore, the Research and Development budget is very limited. cheers Pete.
Your thoughts?

Im just tossing this out there as I dont have a really broad knoledge of all things electrical.
What about another small battery to boost the current to the Coil,fixed between the Coil connector and the Coil itself?
Would this work?

Some light reading for you.

Bruce Candy detector explanation

There is not a lot you can do with a coil.....
For all intents it's just an antenna that both transmits and receives , and is nothing more than that.
I suppose they could eventually put some sort of Pre-amp in there, but it would make the coils more expensive and heavier and more sensitive to EMI with not a whole lot of advantage.
They are already giving us many options on the shape that the signal is transmitted and received via the various shapes and sizes, and other than making them lighter, there is not a whole lot of room to move.
There are so many windings in a coil, that substituting the wire for circuit board etched windings would be impractical because of physical size limitations, although , if they stacked etched coils in multi layer boards, the coils would be very stable, but I guess coils are pretty robust as they are, so it would be fixing a problem that isn't really there....

Despite what one manufacturer says, Coils ARE coils, especially monoloops. Anyone who says he is building a coil that will go deeper and be more sensitive than anything else on the market is resorting to a sales spin. Any improvements on the current crop will be tiny increments and not worth the cost of up grading to. We will have to wait for a new detector, hopefully of a completely new technology, to see any great improvement in depth and sensitivity. In the meantime coil upgrades will consist of lighter, more stable and durable coils than the ones we have. You have to remember, coils have gone about as far as they can on the detectors we have and only a new kind of detector with a new kind of coil will be any great help to us.

Cheers, Jim

I have heard that fishing lures catch more fishermen than fish Coils might be a bit the same...

granite2 wrote:......(1)Any improvements on the current crop will be tiny increments and not worth the cost of up grading to......

........(2)In the meantime coil upgrades will consist of lighter, more stable and durable coils than the ones we have......

Cheers, Jim

(1)...A tiny increment may be the difference between hearing a target and not.

(2)....Any improvement that helps me swing longer, be able to concentrate easier and be more enjoyable is worth the cost of upgrading (to me).

Madtuna, I'm talking about increments so small that you won't even notice them. Coils have gone as far as they are gunna go with our present detectors.

Cheers, Jim

Tesoro have been using printed cct spiral coils in some of their detectors for quite a few years now. Work well n very reliable.

the Printed Spiral, is made only by Tesoro for use with pulse induction circuitry. It offers good sensitivity to a broader range of target sizes and improved sensitivity to less conductive targets such as fine gold chains.

G'day guys.

Yeh boys,I'm a little disappointed in coil technology myself. The solid coils I find a little to heavy during a discuss throw and as for the open spoke,well,they just don't cut the wind right so as to get enough lift.Seriously gents I do not believe that coils have gone as far as they possibly could and here are my reasons why.
'
1)coils are not wound to say 99% of their Q factor so to speak.In other words,are not wound to suit a particular machines output performance but more on a + or - the 80% mark,so as to suit the whole range of machines in general.So instead of achieving close to 100% performance.Performance being in terms of of ground stability,ground balance,sensitivity towards various targets etc etc.we end up with a coil that runs at basically a whole lot less than its true full potential.

The second reason,is cost.Cost in terms of the type of wire winding material used,(single strand,multy strand,cheaper quality better quality,etc etc.The way its wound around a particular type mold,type of shielding material used as a covering around the wiring so as to limit EMI,and last but not least the way the finished wiring loop is set or preserved in a mold so as to prevent any possibility of wire movement during operation. All manufacturers know that there are better across the board quality materials out there,as well as procedures,which do contribute to better performance,but at what cost to the consumer and manufacturer as compared to sales and profit margins.

We as metal detectorists are already paying an arm and a leg,living on a belief that this item will be better than that,only to be disappointed time and time again as to the insignificant or minute differences between one product over the other.As far as I'm concerned there's more room out there for improvement across the entire board(coils and machines included)if only the manufacturers would stop thinking of going via the cheaper mass produced quantity,and concentrate a little more in terms of quality,for it is out there and it does exist.Give us prospectors the quality we deserve,are entitled to and stop this bulls**t drip feed system,that is acclimatising us to believe in,by saying that there's nothing more you can do for us or that's as far as it goes in terms of technological improvements.

Cheers kon61.

Adrian ss wrote:Tesoro have been using printed cct spiral coils in some of their detectors for quite a few years now. Work well n very reliable.

the Printed Spiral, is made only by Tesoro for use with pulse induction circuitry. It offers good sensitivity to a broader range of target sizes and improved sensitivity to less conductive targets such as fine gold chains.

G'day Adrian

If they are for PI machines and made by Tesoro, will they work on a Minelab PI gpx machine. Are they a DD or mono type?
http://www.ackertsupplies.on.ca/products/10.5%22-ROUND-PRINTED-SPIRAL-COIL-%252d-FITS-SAND-SHARK-%26-PIRANAH.html

cheers dave

The reason I asked if an in-line power supply could be added to the coil lead is because I am not sure exactly how it all works.
Correct me if Im wrong,but I assumed that the detector sent a signal pulse (similar to a sonar unit) into the ground via the coil. This is then bounced off a metal target and the detector recieves a distorted reply to the original signal.
So if this is the case,is there any power drop between the Battery,the detector and the Coil? Could an in-line power boost give the coil more punch on the first pulse,but not on the return signal so it dosent harm the electronics?
Surely someone can answer this?
Or am I completely off the charts?

G'day Gus.

I thought of letting some other electronic guru member,reply to your question,but I couldn't resist in having a go.I personally don't believe that an inline power supply to the coil lead would serve any purpose for the detectors voltage output to the coil is regulated and dramatically reduced as compared to the detectors input voltage.
The detector does send a signal pulse into the ground,but is not the same as sonar for one is an electromagnetic pulse (such as that in use on the current line of pulse machines),the other is in the form of a sound wave.The electromagnetic wave is designed to penetrate through solid objects such as rock,wood,glass,plastic etc whereas the sound wave is designed to bounce off the so called solid object upon interception.Both the transmit signal and receive signal have to be working pretty much on par with one another in terms of transmit and receive so as to be able to hear and define a positive metallic substance from the surrounding minerals.C'mmon gurus,there must be some electronic whiz out there who could interpret Gus's question better than what I have.Oh by the way electromagnetic waves(depending on their strength) also emit low levels of radiation through the air,which opens up another can of worms as to how safe pulse detectors are towards ones health over the long term.Probably a lot safer than downing a packet of cigarettes a day. Hey Gus,I think I might be off the charts talking crap and not you.

Cheers kon61.

Well dont look at me i just use the things.

If i posted something that sounded technical or looked impressive...it was pure ass.

Not ass Narawwa,I'd say more logical discussion than most.Its about time all manufacturers of both detectors and coils get off this 15 or so years of the same stale technology and moved on to bigger and better,before we all start believing that a jump of 1% over to 2%,is 100% better.

Cheers kon61.

Kon mate, im hearing ya.

Your post that mentions the Q of a coil is a perfect example of a function that could be implemented on the next detector, and functioned by a tuning pot on the coil or lead. Allowing the operator with a visual guide (number screen) to adjust the tuning of said coil that appears a little to high or low.
Not all coils are 100% equal in their performance, so give us a means to make them.
NF gave us a coil that could be changed by way of a switch on the coil/lead....now give us one that can be tuned 100%.....how can this be done the guy up the back asked.??.... not my problem, my job is to whinge about what we want...not design the thing.

I'm hearing you Koni 61. We need totally new technology not some subtle improvement on the same old. If there was the incentive to get it done, it would be done. Geez I wish I was smarter in this area.
I am sure it is possible to make a detector that only signals Gold as well. There must be a distinct signature of a gold target that is unique in some way. cheers Pete.

Well I'm not happy with my coils.

Found bugger all so far

Waz

Gday

I tend to agree that coils built using the current methods have probably come as far as they can, but think that many coils manufactured now are of a much higher quality than they ever have been, improvements in the build of the coils will probably come with all coils being machine built and not hand built, this will give a consisitancy to the performance and finished product.

The only issues I have had with coils is due to the human factor, some having faults due to the person who assembled it, but over all I have been happy with the products I have used, and they are a far cry from what was available even ten years ago, with the weight issue being addressed it was a big plus when super lightweight coils hit the scene.

As far as the electronics side goes, I dont really think they can do much in that area unless something really new comes along, something substantial like from the VLF to Pulse Induction, I would not doubt that there are other systems that have been looked at and trialed, but all these things take time to develope and will have their own specific issues, minelab have been drip feeding us increments in techology as we all realise but I would also hazard to say that they would also realise that the current technlogy has its limits, and would most certainly know how far it can be pushed before there is nothing left to add.

It seems to be an universal thing with detectorists, always looking for the new best thing, a new detector or coil hits the market, and the spin begins, many barely understand the machine they have yet they want to upgrade to the newer one, this hobby seems to be made up of more parts fiction that fact, its the hope and the dream that motivates some people exactly in the way that get rich schemes do, and many want to do it without putting in the hard yards, the gear we use is only as good as the person operating it, and no matter how good the machine, you still have to get the coil over the target.

I have always believed that nothing worthwhile is free, so instead of wasting time dreaming about the next big thing get off your bum and hit the ground, the only relevant factor in detecting for gold is that you simply have to spend the time on the ground, it wont come to you no matter what machine or coil you use.

cheers

stayyerAU

davsgold wrote:

Adrian ss wrote:Tesoro have been using printed cct spiral coils in some of their detectors for quite a few years now. Work well n very reliable.

the Printed Spiral, is made only by Tesoro for use with pulse induction circuitry. It offers good sensitivity to a broader range of target sizes and improved sensitivity to less conductive targets such as fine gold chains.

G'day Adrian

If they are for PI machines and made by Tesoro, will they work on a Minelab PI gpx machine. Are they a DD or mono type?
http://www.ackertsupplies.on.ca/products/10.5%22-ROUND-PRINTED-SPIRAL-COIL-%252d-FITS-SAND-SHARK-%26-PIRANAH.html

cheers dave

NO and Mono

http://www.nuggetshooter.com/articles/UnderstandingPIdetector.html
Here is a link to an article by Reg Sniff on Bill Southerns website. One of the best explanation of how a detector works in words that most can understand. Enjoy.
Frank

Understandably a tunable coil presents problems if the detector is unable to relay the tuning to the operator. Yet i think the idea is sound knowing that problems with certain brand coils were not entirely interacting with the 5000 when released. This may have been due to many different reasons.?? The detector called for a more precise parameter in the coil from the posts i read was one. Yet it may have been a problem thats tunable in the future.?
To think coils have come as far as they can is simply not thinking clearly. Is it not possible to add new ideas to the shielding, cable placement, diameters and configurations.? NF not long ago put out the 30x7, when has that configuration been used before on a commercial level.? It maybe the same technology inside but it keeps some of you busy.

Couple the coil with better shielding and the rest of the coil characteristics matter little due to the coil now being seen as the best defense against EMI, which we all know is just the pits due to detectors being more sensitive.
EMI is not going to leave us anytime soon, thinking ahead in terms of better defense against EMI from the area where its causing the most problems is a big milestone, even if the rest of the coil hasn't changed.

I bought a brand new Commander 15X12 DD not long after they first came out. $320
Whats changed in it that warrants the price rise @ $390 today???
Does it still feel like your swinging a BBQ plate.?

Both the Bruce Candy Link and the Reg Sniff link make for educational reading.

My questions ...did SETA come out before or after those write ups.?
What was the primary objective of the Smart ElectronicTiming Alignment, and did it achieve all it could/can.?
Is it able to be improved upon.?
http://www.minelab.com/consumer/knowledge-base/minelab-technologies

Has the PI platform reached its end, or that of coils as we know them.?
I doubt it.

Its a strange thing that the old green 18" round monoloop (not the rubbish bin lid) designed and built back in about 1996 works as well today on todays machines as any other monoloop of comparable size. And it was pretty light as well.

All improvements have been with the machine and not the coil. As for drip feeding: I agree. Henry ford could have given us the the fords we drive today instead of having to wait all those years for them.

Cheers, Jim

How many people are using a ferrite sheild on their coil wire before it goes into their control box? There's a reason that good USB cables have that little "donut" on them. It prevents stray electrical interference. The coil cable itself its an attenna. (Especially if you are around overhead or underground wires.) You cleanup the signal and you will get a lot fewer false signals.
(I use one on all my machines that have wires.)

In the new XP Deus machine they have gotten rid of wires all together. The coil is powered with a lithium cell, the control box is powered with it's own cell as well as the headphones.

"Look Ma, no wires!"

Current wireless headphones (Airheadz to name one) rely on Blue Tooth circuitry like cell phones. Again, highly receptable to electronic and magnetic interference. The XP Dues uses a proprietary RF frequency.

I think in the next 2-3 years, you will see all detectors going to route. IMO

hmmm maybe fractal antennas are the answer

http://en.wikipedia.org/wiki/Fractal_antenna

Funny thing about technology, I still use Windows Publisher 95 on my Toshiba laptop with Windows seven. 95 does everything I want and its lightning fast on windows 7. No wonder old coils still work well on new detectors.

But seriously, the new Coiltek 14x9 Blitz is tuned specifically to the GPX5000 and is just a little better than any coil not tuned specifically to the detector it is used on.

Cheers, Jim

But seriously, the new Coiltek 14x9 Blitz is tuned specifically to the GPX5000 and is just a little better than any coil not tuned specifically to the detector it is used on.

I shall as soon as the sun rises, return my blitz coil to the place of purchase for a full refund, as its not suited to my 3500 after reading this.
Why was this not mentioned by the dealer as i told him i had a 3500.???

Umm?? little thought went into that statement mate. Im sure the owners of the older model detectors who just went out and bought the blitz series, than reads this will react in a similar fashion i did with my scenario above.
Care to elaborate to those who now feel a little peeved ant their purchase, and to those of us who were just about to jump fence.??

How many people are using a ferrite sheild on their coil wire before it goes into their control box? There's a reason that good USB cables have that little "donut" on them. It prevents stray electrical interference. The coil cable itself its an attenna. (Especially if you are around overhead or underground wires.) You cleanup the signal and you will get a lot fewer false signals.
(I use one on all my machines that have wires.)

The coil lead is shielded, and cannot be picked up by running the coil over the lead. So if your unable to pick up the cable from a working detector, what chance has interference from a far source able to compromise it.?
If there was any real benefit from having one of these ferrite thingies on your lead.....it would be gospel and well known world wide on all prospecting forums. I did read that one of the dealers in Vic was selling them or perhaps it came out on the coil...cant remember.....yet for the likes of me i can not understand why such an improvement is being .....suppressed.

Just behind the front end cap of your GPX series, you'll find the ferrite thingy already in place. Older models employ them as well. They are connected to the coil wires, however i doubt there function is purely for the outside EMI problem we despise, however if that is its primary function .....how disappointing.

If your going to buy one of these ferrite thingies, be sure to match it to the frequencies they are to suppress.

Narrawarra, while the Blitz coil is wound specifically for the 5000 it will also work better on all GP's better than similar coils. It is a great all round coil. As for getting a refund you will find that all advertising I have seen concerning the Blitz specifically says as below. The following was taken direct from the Coiltek Gold Centre's website.


Specifically wound for the new GPX5000 detector this coil, coupled with the 'FINE GOLD' setting, has the potential to brighten up those faint targets, especially the smaller pieces at depths only seen on the new GPX5000.

The coils ability utilises the already popular shape and size of the 14x9" coil providing excellent manoeuvrability and sensitivity for pinpointing and depth

Cheers, Jim