Larger Coil for more depth

[cashmole]

Hi guys I am posting this here because I think you guys may have a better idea and a larger pool of Etrac users to Safari users and similarities of both the Safari and Etrac:

I have been looking at larger coils for my Safari(this should apply to the Etrac as well.) I want more depth but I hunt city parks that are moderately trashy. Some have high trash but most are mid level for city parks. Anyways I find that 6" older 1950's to 1960's pennies don't come in super strong. They are a high tone with some "clipping" to the signal. This is how I can tell it is an older deeper penny. But shouldn't a 6" penny be crystal clear? I was thinking of getting a slightly larger coil to get a few more inches of depth and possibly be able to hear the older deeper coins but I don't want to miss good targets because of using a big coil in a city park with its trash.
I was looking at a Nel Thunder (14.5"x10.5") or Cors Cannon(which I believe is a re-branded Nel Thunder). Also looking at a Cors Strike which is a 12"x13" coil. I like the Thunder/Cannon but width is 10.5" compared to the stock Safari 11" wide coil. Will this coil get me any more depth(being 14.5" long as opposed to 11" long on the stock coil) or will it be the same in depth because of the relatively same width regardless of it being longer. Or will the extra length help with depth some. OR should I get the Strike because it is an overall larger coil? Any suggestions?

 

[expII al]

I use the WOT coil. Goes deep and is very sensitive. Great coil but a little heavy but worth using.

 

[IDXMonster]

According to "conventional wisdom" the width of the coil has more to do with depth than the length. For sheer depth,following this "wisdom", then the 12x13 would be what you're looking for out of the ones mentioned. Because of the fuzzy corrosion that occurs on copper coins in most places, pennies at that level can certainly sound broken and sketchy. Repeatability with numbers that are close is the key. Silver at that same level will sound better,usually,because they don't corrode. Personally,I have found that around here, having a big coil that generates a larger field is the key to deep coins. Some places with heavy trash won't be as easy to find coins in,just because of too many things in the ground. You might get lucky and find a 10" coin in amongst heavy trash just because of the angle of attack,but generally...heavy trash=small(er) coil....

 

[metalpopper]

IDXMonster
According to "conventional wisdom" the width of the coil has more to do with depth than the length. INCORRECT

FACT:- Length AND width, both determine a coil's ultimate depth potential. (Width / Length RATIO, determines a coil's ECCENTRICITY....field distribution.)

Silver at that same level will sound better,usually,because they don't corrode.... INCORRECT

FACT:- Silver can/does corrode; dictated by ground chemistry, etc.


having a big coil that generates a larger field is the key to deep coins. Fundamentally, CORRECT

Hope that helps...Matt

For sheer depth,following this "wisdom", then the 12x13 would be what you're looking for out of the ones mentioned. Because of the fuzzy corrosion that occurs on copper coins in most places, pennies at that level can certainly sound broken and sketchy. Repeatability with numbers that are close is the key. Personally,I have found that around here, having a big coil that generates a larger field is the key to deep coins. Some places with heavy trash won't be as easy to find coins in,just because of too many things in the ground. You might get lucky and find a 10" coin in amongst heavy trash just because of the angle of attack,but generally...heavy trash=small(er) coil....

 

[sprchng]

I have tried the Ultimate and WOT and found the 10 x 14 Detech excellerator coil to be the best value and deepest with the best separation and sensitivity in my dirt on the etrac, Safari may be different and you will have to contact the Detech factory to get one. Have not tried the NEL large coils

 

[cashmole]

Thanks Matt and all others that responded. I kinda thought length and width determine the depth. I may have bought the 14.5"x10.5" coil had I seen your post earlier. I ended up getting the 12x13" Cors Strike. I'll let you all know how it is when I get it. The 14.5x10.5 may have been better but I didnt want to risk not getting any better depth from stock.

 

[sube]

Coil Shape The most common coil shapes are round and elliptical. They are available in solid and open-web designs. Elliptical coils are more manoeuvrable without sacrificing ground coverage. Round coils are often more stable, higher performing, and achieve greater depth. Open-web coils are waterproof, help cut through water and assist when pinpointing because the ground is visible through the coil. From minilabs coil selection guild knowledge base .

As far as silver corroding very few coins in my dirt so for me I would also say silver don't corrode now salt water and different soil make ups I would say yes .

You be the judge round or elliptical. sube

 

[Bryan V]

I have always read that coil width is more influential on depth then then the coils length.
I have both the Nel Thunder and Tornado. The Tornado is deeper by around 3/4" in my testing.

Not long ago I had emailed a coil manufacture with a new coil idea.
The founder and CEO responded and this is part of his quote.

"Usually the width of the coil points to the maximum depth on a coin of 1 euro."

 

[IDXMonster]

And I did forget about saltwater and the tarnishing that any water brings over time...saltwater apparently being quite vicious on coins!
A lot of people using the 13x17" CTX coil report gains of 1-2" in many cases,myself included. Although it's 6" longer,it's 2" wider,which corresponds more to the data guys report. The DDs in manual sens sure like to grab whatever is around....one of the reasons auto is what I mainly run.
I hope the OP has gotten the info needed in this thread.

 

[Silver Saver]

I think you made a great choice there cashmole. A lot of people really like the nel tornado on the etrac which is pretty much the same coil, they say it hits hard on the deeper coins. The only downside is it's a heavier coil. I like my older style WOT and sunray x-12 in that respect because they have no webbing and are lighter. WOT is sensitive and hits deep.

 

[daddyflea]

I disagree that bigger coil in a park setting is going to only get more blending and less ID. Get a Sunray 8" or a Coiltek 10X5 and you will get coins all day at 8" or better. I get deeper coins with the smaller coils because they ID much better. Without good ID you might as well dig all signals

 

[metalpopper]

I have always read that coil width is more influential on depth then then the coils length.
I have both the Nel Thunder and Tornado. The Tornado is deeper by around 3/4" in my testing.

Not long ago I had emailed a coil manufacture with a new coil idea.
[size=x-large]The founder and CEO responded and this is part of his quote.

"Usually the width of the coil points to the maximum depth on a coin of 1 euro.[/size]"

**************************

Hello Brian, Whoever the guy was, 'CEO' (Chief entertainment officer ?) for he was certainly not a coil designer or technically savvy.

The only meaningful part of his statement, was that of referring to the target coin.

I put his reply on a par with the bits of paper from a Xmas cracker.

He should surely have given a better answer for any coil they manufacture.

Every coil has a baseline figure, for a specific coin, at a defined frequency..IN AIR.

You can't expect 'soil-figure-depths', for they are variable/ground dependent , non-standard.

Never use a bi-metal coin as a reference target. OR a clad ferrous cored coin.

Any older copper/bronze will be OK. DO YOU HAVE ONE IN YOUR COLLECTION?
if so, can you give me its diameter and thickness figures?

What is the date of manufacture for your NEL TORNADO?

Let's see if we can better analyse the Thunder V Tornado......matt

P.S. What coin (and its date) did you use in your comparative testing of Thunder V Tornado ?

and what were the actual depths for each coin?....AND...what was your manual sensitivity, for the test?

 

[Bryan V]

I have always read that coil width is more influential on depth then then the coils length.
I have both the Nel Thunder and Tornado. The Tornado is deeper by around 3/4" in my testing.

Not long ago I had emailed a coil manufacture with a new coil idea.
[size=x-large]The founder and CEO responded and this is part of his quote.

"Usually the width of the coil points to the maximum depth on a coin of 1 euro.[/size]"

**************************

Hello Brian, Whoever the guy was, 'CEO' (Chief entertainment officer ?) for he was certainly not a coil designer or technically savvy.

The only meaningful part of his statement, was that of referring to the target coin.

I put his reply on a par with the bits of paper from a Xmas cracker.

He should surely have given a better answer for any coil they manufacture.

Every coil has a baseline figure, for a specific coin, at a defined frequency..IN AIR.

You can't expect 'soil-figure-depths', for they are variable/ground dependent , non-standard.

Never use a bi-metal coin as a reference target. OR a clad ferrous cored coin.

Any older copper/bronze will be OK. DO YOU HAVE ONE IN YOUR COLLECTION?
if so, can you give me its diameter and thickness figures?

What is the date of manufacture for your NEL TORNADO?

Let's see if we can better analyse the Thunder V Tornado......matt

P.S. What coin (and its date) did you use in your comparative testing of Thunder V Tornado ?

and what were the actual depths for each coin?....AND...what was your manual sensitivity, for the test?

Matt I did not quote the entire response from the CEO since it was a private conversation. His response was just fine for the context in which it was stated.
As you can see in the quote he said "usually". This was not a deep technical conversation we were in.

As for your request for more information about my Thunder vs Tornado testing you can read it here on a May 5th post.
http://www.findmall.com/read.php?63,2363950,2366766#msg-2366766
Both of my coils were purchased new this spring.
Bryan

 

[nge]

I hunt "floodplain" parks and where the deep dirt is usually moist year round, some of my silver comes out blackened......NGE

 

[Clad2Hunt]

I just got the Tornado and had a short beach run. Had to mess with the threshold because I use ear buds and the surf is roaring at times. Once I got use to it I noticed it would hit harder on deeper targets than the pro and it pin points like a dream for a larger coil. I had a Tornado several years ago and the cable on this one slides right through the tube when mounting unlike the older one which I had to use a pull string to get it through the tube. It is sensitive to smaller targets. Got 2 ear posts with one having the stone missing and hard to see in the sand but the MD had no problem. So far I haven't spent anytime in the dry sand but that will happen this weekend and should be able to crank it up. Have to back down in the wet sand but still impressed with the depth.

 

[metalpopper]

Thanks Matt and all others that responded. I kinda thought length and width determine the depth. I may have bought the 14.5"x10.5" coil had I seen your post earlier. I ended up getting the 12x13" Cors Strike. I'll let you all know how it is when I get it. The 14.5x10.5 may have been better but I didnt want to risk not getting any better depth from stock.

****************************

Hello again Cash!

The 12"x 13" will indeed (in theory,) get you about another inch or so more than the Thunder on a 1 inch diameter coin, or larger; (of 45 CON. or more).
.
Proportionally less as the coin size decreases, or the conductivity diminishes. Basically, the 12"x13" should go deeper than the Thunder.


So if you've bought 12x13 already, and you simply want more depth, then you've made the right choice.
What is not absolutely predictable, is the suitability in terms of functionality in trashy situations. So that aspect is a matter of luck.

The 14x10.5 Thunder has a narrower response field than the 12x13 Cors; but a slightly longer capture profile.
That's the ECCENTRICITY factor coming into play, but complicated by different dimensions involved.

In my opinion, The Thunder would be less susceptible to trashy conditions......but when trash does give you problems, raising your coil, and/or circling the target, may resolve matters

Good hunting, matt.