coils for coins

[emubob]

what is the better coil for finding coins in a park/field setting,concentric or widescan?

 

[John-Edmonton]

I stick with concentric coils. DD coils tend to read a lot of quarters as bottle caps. Concentric coils also give much more accurate ID.

 

[BH505Man]

I wouldn't be so quick to dismiss DD coils because they are better than concentric coils when searching in highly mineralized ground.

 

[D&P-OR]

Excellent point!

I wouldn't be so quick to dismiss DD coils because they are better than concentric coils when searching in highly mineralized ground.

 

[GeorgeinSC]

I prefer a DD coil for the following reason.

https://www.bigboyshobbies.net/double-d-coil-vs-concentric-coils/

 

[dfmike]

I'd probably say DD if your in the USA and you probably are. In Canada, the concentric coil has its advantages because I find it better to sniff out our nickel plated steel clad. It rarely identifies them as iron trash and the ID on them doesn't sway as much as with a DD. Of course this is machine dependent to some extent as well. I do find that in our moderate to high mineralized dirt, the DD coils of similar size go slightly deeper.

I know a lot of people will say that they have no difficulty pin pointing a target with a DD coil but from my experience with both, the concentric is far superior for that as well. That means small plugs, no need for x patterns and target in the center of the plug every single time (that also means no damage to the target). I find with DD coils bigger than the typical stock 5 X 10, it becomes more approximate.

I started with concentric coils, switched to DD for a couple of years and now back to the concentric. I like both and use both.

 

[REVIER]

I hunt in the SE. with some pretty good red clay mineralization.
DD's were always said to be better in mineralization but in the hundreds of hours experience I have hunting here using two different detectors that use both DD's and concentrics I haven't seen a huge difference.
Some but nothing earth shattering.
Here both my detectors are pretty close to each other using both kinds of coils...a lot closer than I would have thought.
The DD is a bit deeper with better ID's, sometimes, but depth is pretty curtailed here using most machines and coils so both kinds of coils seem to get similar results in most, not all, of my sites.

When I hunted in great soil in Kansas and Missouri a big 11" DD coil definitely got deeper than my 10" concentric, definitely at least a 2" but even up to about a 5 -6" depth difference in a few rarer instances but I believe that had to do more with the size difference rather than the design.

The DD's struggle with pop tops due a bit less sharper discrimination, using a Tesoro with no screen I usually just avoided using them if possible because it was a big hassle that slowed me down dealing with them in trashy sites, using a Fisher with a screen it really wasn't an issue.
What I did feel was different was how my detectors behaved over coin and especially jewelry targets, more so with my Fisher than my Tesoro.
Using a concentric I felt the tones were just a bit better using concentrics over those type of targets, sharper, clearer with a sound I can only describe as "sweeter".
Maybe it's just me but after many hundreds of hours using both kinds I can tell a difference, every time I switch back to a concentric after using a DD that first clear tone I hear over a coin always makes me smile.
In a park setting with lots of trash in both good and bad dirt while searching for coins and jewelry unless I needed to go super deep where every 1/4" mattered I lot for the concentric more often than not.

 

[Monte]

what is the better coil for finding coins in a park/field setting,concentric or widescan?

This has been a very interesting point of discussion for many decades, and all too often they are presented as you have 'emubob' without specifics. Without specific qualifications to answer you will get a wide variety of 'opinions.' Now, 'opinions' are not bad, as long as they are properly founded, but way too many people who enjoy this great sport do not really understand facts, such as search coil types. Also, the shape of a generated Electro-Magnetic Field, nor how Ferrous-based [size=small](magnetic)[/size] objects have a differing effect on the EMF than Non-Ferrous targets.

So many Hobbyists just don't comprehend the differences between the shape of a generated EMF as compared to the reactive portion of that field. To make things even more complicated are the way too generalized questions, such as yours where you asked what is better for coins, a Concentric or a Wide Scan [size=small](aka Double-D)[/size], or the size and shape of the specific coil, or mention of the particular metal detector planed to use a search coil, and also not specifying the type of alloys used in the coins being sought. Finally there needs to be some clarification of the type of ground mineral environment where the search is being conducted.

All too often we will share an 'opinion' that is based on incorrect information we have read or heard, and frequently things are in print that are not quite correct. For example, let me refer to a cut-and-paste from a ling indicated below:

Everyone wants to get that extra advantage with their metal detector. One of the ways to get extra out of your machine is to get a situation specific detector coil.

That's partly correct, but it is quite probable to start out by getting a "situation specific detector" or a logically better coil might not be of any benefit.

When you have the right metal detector coil for the right job your good detecting finds can go drastically up. You wouldn't want to use racing slicks on a mud course at the track. Same applies to metal detectors.

It really ought to read: "When you have the right metal detector AND coil ...."

Now what kinda coil is right for me? Smaller coils are usually more sensitive and get better separation. Bigger coils get better depth but can mask close targets. Each metal detecting situation is different and certain coils have advantages different places.

On this point I almost totally agree, and I have been a fan of smaller-size search coils since 1971/'72. And usually it is correct that bigger coils will get better depth. But there are times when a smaller-size coil can get better depth in a trashier environment because they can work between some debris and go a bit deeper whereas a larger coil can't due to an altered EMF.

Most of the time the stock coil will give you the best results for that specific metal detector.

I think that was pretty close to true until about 1988 depending upon the manufacturer's decisions, but since then, and especially since about ±2000 or so, we have seen distorted ideas on 'standard' search coils sizes and designs by many detector manufacturers. It used to be that most 'standard' size coils were about 6" to 8" in diameter. In '88 White's started offering their new '950' Concentric coil on all their upper-end models and they promoted the reason for the new coil was because the consumers wanted "more depth."

But for many of us it was counter-productive, and I remember sitting in the audience at the Texas Council of Treasure Clubs get-together in '88 when Alan Holcome, from White's Electronics, started out his presentation by letting everyone know they made a new coil, the reason was because enough consumers claimed they wanted more depth, but he told everyone that in his opinion he felt they made a mistake. The 8" Concentric coil was still the better "general purpose' search coil in his opinion. I was in agreement with him then, and I continue to have a similar agreement today. But that trend of "bigger-is-better" has carried on with almost every detector manufacturer to this very day.

About 2000 or so there was enough influence by the newer Minelab offerings that started more-or-less a trend to go to a larger-size and Double-D designed search coil, even on lower-cost so-called entry level detectors, and it gets even worse when the detector itself falls short on performance by having a slow or delayed response and recovery time. That's why we have been able to see the growing number of people with a newly-released model cry out for a smaller-than-stock accessory coil, because the 'standard' coil is simply the wrong size or type for most average hunting tasks.

Metal Detector manufacturers spend many hours trying to get the best all around coil for that detector.

I think that used to be more true in the past than it is today.

Right now the two main coils are the (DD) and the concentric or also named (mono loop) coil.

There are two very popular coil types: The Double-D [size=small](also called a Wide Scan)[/size] and a Concentric. A Concentric coil, like the Double-D, has two primary internal wire windings, a Transmit and Receive. The Concentric is NOT a 'Mono' coil which only has one winding. A 'Mono' style search coil is the type used on a Pulse Induction model or like those search coils many of us "old timers" started out with when using a BFO [size=small](Beat Frequency Oscillation)[/size] detector.

The concentric coil puts out a snow cone-shaped field (shaped like a snow cone),...

WRONG. A generated EFM that radiates about the Tx winding is NOT a "snow cone shaped" field at all. In years past we could see an accurate depiction from Garrett Electronics [size=small](now Garrett Metal Detectors)[/size] as well as Tesoro Electronics that showed the general appearance of the generated EMF about a search coil.

... the DD field is more like the "knife blade" of the concentric (shaped like an I).

WRONG, again, especially suggesting the DD projecting a "knife blade" Concentric field.

The drawings or images shown are not a true depiction of the generated or projected EFM, and they still are not quite correct at showing the reactive portion of the EMF which is really what we need to be aware of when considering the type of search coil to select. Both coil designs have a 'tapering' reactive area in their generated field, and yes, the Concentric type coils will have a more narrowing appearance than the Double-D types at the greater extent of their functional field, but both coil designs have a tapering or diminishing 'reactive portion' in their generated EMF. And there are still significant differences between the two coil types in the way of performance.

The DD coil separates much better and gets more even depth especially in mineralized ground.

WRONG, again, because a lot still depends upon the metal detector itself and how the circuitry design handles ground mineral signals, combined with the search coil's size and the shape or lay-out of the internal windings of both coil types.

I have evaluated an uncountable number of search coils for well over five decades and, yes, there are some coils on some detectors that show some edge in performance so far as 'separation', but I can show very obvious advantages in favor of many Concentric search coils when it comes to the detector and coil working well with a 'Quick-Response and Fast-Recovery.' I never make a blanket this-or-that answer to such things as 'separation' or 'depth' or other in-the-field performance characteristics without first evaluating the specific search coil sizes and types on specific metal detectors. Way too many variables.

Overall, I guess I would say that I have generally preferred Concentric designed search coils for the bulk of the time I have been into metal detecting and that it well through my 54th year. And Double-D coil designs for recreational metal detectors has been around a while, also, as that design was pioneered by Compass Electronics in their Yukon series of TR's in 1971 which is when I first started using any Compass detectors. So I am well aware of that coil design and the pros and cons with regard to how they might perform on different detector circuitry designs. I have 13 Regular-Use Detectors hanging on the wall here in my den, and of them, only 4 of the 13 have a DD coil mounted. The rest are all at-the-ready with Concentric coils.

In my 'Specialty-Use' Detector group, that I have on-hand for Seminars of Presentations to show what we had and where we've come from, I have 2 '70s era Compass TR models w/DD coils, 1 '60s era Garrett BFO w/small dual [size=small](Mono type)[/size] coil, 2 mid-to-latter '70s era Garrett TR-Disc. models with 1 equipped with a DD and the other Concentric, and one '81 50 kHz Garrett TR-Disc w/Concentric, plus an '86 Teknetics Mark I Ltd. w/Concentric coil.

One reason I have the selected coils mounted on my Regular-Use Detectors is due to their field performance and 'separation' abilities. For 4 of those 9 models with a Concentric coil mounted I do have some DD coils in my Accessory Coil Tote should I feel a need to use them.


--- And from another cut-and-paste from that link: ---

The pictures above show the detection fields of the two coils, the concentric and DD coils. The lines show the search field penetration of the two different metal detector coils.

An inaccurate/incorrect depiction. Maybe close in some ways, but overall incorrect.

From the picture you can see why as was said why the DD coil can separate better than the concentric or mono loop coil.

Again not correct, and again, it isn't a 'Mono' coil if we are comparing Double-D and Concentric designs.

One of the bad things about the DD coils is sometimes bottle caps are harder to tell from good targets.

CORRECT, and note here the reference is made to 'BOTTLE CAPS' which are a man-made object out of a mix of ferrous or magnetic property metals, and not a higher-conductive and non-magnetic metal. Bottle Caps can be a problem for many modern metal detectors whereas they were not as troublesome with a good conventional TR or TR-Disc. model. The motion-based Discriminating circuitry that tries to cancel out the ground signal and problem trash signals simultaneously have had struggles with Bottle Caps, and similar annoyances like rusty tin, ever since they entered the scene about '78 with the Bounty Hunter Red Baron. And Concentric coils can handle the effects on an EMF better than most DD designed coils can. Different shaped fields, winding lay-out, and different behavior from ferrous objects vs non-ferrous objects.

With a little practice and keen ear to the audio one can tell the tell tale signs of a cap. Usually falsing at the tip or heel of the coil is a great indicator.

True and false. True that a trained-ear operator can tell a difference between a likely ferrous or non-ferrous object. This is a technique I've used and taught for decades and I refer to as Audio Target Classifications. However, it is incorrect to refer to the 'tip or heel' of a coil indicating a 'false' signal.' Instead, it is the tip and tail of the coil that can produce the proper or correct signal on Bottle Caps and the sweep across the center-axis of the coil is the false response in most cases.

Keep in mind that here he specifically said 'cap' without clarifying it as a magnetic metal based Bottle Cap. Do not confuse these with the Screw Caps which are made of a non-ferrous, and higher-conductive metal.l The aluminum Screw Cap doesn't cause the errant audio falsing of the Bottle Cap.

I personally LOVE the DD coil. I feel the advantages of depth and separation greatly outweigh the negatives of digging a few screw caps.

Here we differ because I personally prefer a Concentric coil most of the time, depending upon the detector model in use and the available search coils. Often there isn't a real advantages in Separation between two comparable-size DD and Concentric coils, depending upon the site environment. Also, size-for-size, it is known that a Concentric search coil will almost always match or better the depth-of-detection of a DD coil. Also, he changed his reference of a pesky 'cap' to a Screw Cap, and those aren't the issues we were looking at.

I also will prefer a smaller coil over a bigger coil in most situations.

100% AGREEMENY on this point, which is why I do not have any of my 13 Regular-Use models outfitted with a 'standard' search coil. They all have a smaller-size or mid-size coil mounted to better handle the majority of sites where they are going to be used.

Yes bigger coils get more depth but the main trouble I see is not the depth it is the target mashing of trashy areas. I have found more good targets with the stock coil or smaller coils.

Again, 100% agreement and why I use smaller-than-stock coils for about 98% of all my detecting.

Just my experienced opinions, and with more detailed information about the specific detector and search coils you'd be considering I am sure you could get a much better response from other experienced Detectorists.

Monte.

 

[Monte]

I hunt in the SE. with some pretty good red clay mineralization.
DD's were always said to be better in mineralization but in the hundreds of hours experience I have hunting here using two different detectors that use both DD's and concentrics I haven't seen a huge difference.
Some but nothing earth shattering.

I live in the W/NW chunk of the USA, in far Eastern Oregon, and mainly hunt here, in Utah and Nevada as well as other states when I get around.. In my travels I have encountered and hunted some "red clay" that, while maybe not your red clay, certainly posed some interesting challenges. Most of the places I search are comprised of a heavy dose of iron contaminated ground and easily fit the 'highly mineralized' category, so much that it makes me envious every time I have ventured into some very 'kind ground' like when I have hunted in Texas, Oklahoma, Missouri, Kansas, Nebraska, Florida and a few other places.

And I've tackled all the challenges using both Double-D and Concentric coils, especially the latter, and I have done it with a wide assortment of makes and models of detectors. Today, in my Regular-Use Detector Outfit, I have thirteen detectors comprised of nine models, and by this time next week that count will be fourteen total and ten different models. With a few specific detector designs, I get very acceptable in-the-field performance with DD coils. With a few other I have now or have-had, they use both search coils types and generally the Concentric designed has proven to be the best pick. Out of my current detector Outfit, I do have DD's in my Accessory Coil Tote on spare lower rods for some models, but I keep four devices at-the-ready with a DD coil mounted and the other nine sport a Concentric coil that I feel handles most day-to-day hunting I would do with them.
.

Here both my detectors are pretty close to each other using both kinds of coils...a lot closer than I would have thought.

I have found the same to be true, that most of the Concentric coils, on my preferred detectors of choice, are very capable in higher mineralized ground for my Coin & Jewelry Hunting, or for Relic Hunting which is what I do most of the time. Now and then I can sense a slight edge one way or the other in really challenging ground, but not enough to praise one coil type over the other in general description.

The DD is a bit deeper with better ID's, sometimes, but depth is pretty curtailed here using most machines and coils so both kinds of coils seem to get similar results in most, not all, of my sites.

Here we differ because Concentric coils easily provide more consistent visual Target ID/VDI responses than a DD, and they also are more capable and consistent when it comes to Discrimination.

When I hunted in great soil in Kansas and Missouri a big 11" DD coil definitely got deeper than my 10" concentric, definitely at least a 2" but even up to about a 5 -6" depth difference in a few rarer instances but I believe that had to do more with the size difference rather than the design.

I've found that with comparable-sized coils the Concentric specimens tend to get slightly better depth-of-detection, but seldom does one style coil get huge bragging rights over the other. It all depends on the particular detector the coil is mounted to, the settings, and the ground mineral challenges.

The DD's struggle with pop tops due a bit less sharper discrimination, using a Tesoro with no screen I usually just avoided using them if possible because it was a big hassle that slowed me down dealing with them in trashy sites, using a Fisher with a screen it really wasn't an issue.
What I did feel was different was how my detectors behaved over coin and especially jewelry targets, more so with my Fisher than my Tesoro.
Using a concentric I felt the tones were just a bit better using concentrics over those type of targets, sharper, clearer with a sound I can only describe as "sweeter".

Yep, the DD doesn't Discriminate as well as a Concentric and really has difficulty with Bottle Caps. That's mainly due to the effects of their opposing yet overlapping Tx and Rx and windings and the inconsistent effects of the signals to process from a right-to-left sweep and an opposing left-to right sweep.

Maybe it's just me but after many hundreds of hours using both kinds I can tell a difference, every time I switch back to a concentric after using a DD that first clear tone I hear over a coin always makes me smile.
In a park setting with lots of trash in both good and bad dirt while searching for coins and jewelry unless I needed to go super deep where every 1/4" mattered I lot for the concentric more often than not.

Been using DD coils since '71/'72 and early on I learned their strengths and weaknesses and I have no trouble using them on my favorite detectors. But ,like you, a change-up in detectors to one using a Concentric coil does give me a different level of 'satisfaction'. Oh, and in all cases, I use mainly smaller-size to mid-size search coils and hardly ever use a 'standard' search coil on any of my detectors.

Monte

 

[Ozleif]

what is the better coil for finding coins in a park/field setting,concentric or widescan?

Mr R.

At present only DD coils are available for the Equinox, on the Cairns esplanade I would use the EQX 06 Double-D Smart Coil.