500% more???

[b3y0nd3r]

In an article "BENEATH THE MASK" by Tom Dankowski he states:

"If a 8" coil can 'see' a one gallon volume of dirt and the 11" coil (not 10.5") can 'see' 7 gallons of dirt at any given time, it is a fact that you are 7 times more likely to 'mask' a object with the larger coil, especially in trashy areas. It is so easy to get into trouble with the larger coil AND NEVER KNOW IT!"

Brilliant for sure, but what about other factors? What happens when you crank up or drop the gain/sensitivity? What happens when you increase/decrease your sweep speed? How about proximity of the coil to the ground? What about the ground itself? What if it is highly mineralized or very little mineralization?(those were rhetorical questions) There are a monstrous amount of factors that can increase/reduce masking.

I recently have acquired a super sensitive Impact. It was constantly hitting low conductor targets, they were tiny, but the response was that of a high conductor at certain angles. I knew they were not good targets, I wasn't fooled, but i dug them anyway. That prompted me to think that. too much gain/sensitivity, can mask targets too. How many of us set the gain/sensitivity at high and never change it throughout the entire hunt?

He also states that:

"When you discriminate iron with any detector (Minelab calls it "iron mask") you have achieved nearly nothing. (Simply, there will be no audio response reported in the headphones). The detectors electromagnetic signal is still disrupted by the iron"

If you think about what this really means, it means that you can't ignore something without detecting it first, and if you detected it, then you can't ignore it. There really is no way to rid iron(besides digging it). All you can do is work around it.

Further in the article he states:

"Nine (9) coins were found with the CZ. Thirty-nine (39) ADDITIONAL coins were (unmasked) found with special equipment. Forty-eight (48) coins in total. Looking at the ratio a bit differently; 9 of the 48 coins were detectable by a top-line coin detector. Thirtynine additional coins--- that's over 500 percent MORE coins,,,, were masked! Yes, unsuspectingly, this is THE norm!"

When I first read this, I did a triple take. 500% more coins were masked? I didn't believe that. Who could? Well, I was wrong.

A local park was being redone and the dug down about a foot. After securing permission, I took my CTX 3030 and went to work. I found mostly clad and junk, nothing old. I used the standard and the large 17" coil. After a few days I thought it was cleaned out then the foreman came over and said "we are removing two more inches tomorrow". I thought "two inches? Big deal." I went else where the next day and drove by the park with an hour of so daylight left. I stopped and thought, "what the hell, lets just see". All of the sudden there were targets everywhere. Wheats, indians, V's, Buffs, a large cent, a crotal bell(no silver). All just two inches that the CTX couldn't see.

So 500% more? You bet your azz!

Thanks for reading

 

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[Treasure_Hunter]

I hunt with large coils all the time on my excals and I get targets extremely deep with it that the 10 inch never sees, same with the 10" coil, it sees target the 8" never sees, test garden has shown that dozens of times. When hunting with my 3030, I am usually using the 11" although on occasion I do use my 17".

 

[b3y0nd3r]

I hunt with large coils all the time on my excals and I get targets extremely deep with it that the 10 inch never sees, same with the 10" coil, it sees target the 8" never sees, test garden has shown that dozens of times. When hunting with my 3030, I am usually using the 11" although on occasion I do use my 17".

If I ever come down to FL, please show me your hunted out spots

 

[Charlie P. (NY)]

I'd like to see the math for an 11" coil seeing 7X what an 8" coil can.

Even "per sweep".

8" conical "sees" a cone of 117.29 sq in. while an 11" coil "sees" 348.45 sq in. Three times the volume (assuming the field is one coil width deep). He's just basing it on finds - but how can you ever prove they were evenly dispersed in each test?

DD coils "see" a 2" wide by coil length "U" shaped field and I'm not that determined to try and figure those differences.

 

[cudamark]

Sweep speed and processor recover speed play a major roll in whether you have a masking problem or not. Who knows what was in that 2" of dirt. It might be that other coil sizes wouldn't have found anything either. It might just have been getting that much closer to the target in bad ground and nothing to do with coil size.

 

[b3y0nd3r]

Not being defensive here so this is just a matter of fact tone:

"I'd like to see the math for an 11" coil seeing 7X what an 8" coil can."

Tom D, is literally a rocket scientist who works for NASA. I would take his math any day.

"Sweep speed and processor recover speed play a major roll in whether you have a masking problem or not."

True. I eliminated all factors I could control BEFORE those two inches were dug. I wanted to make sure there was nothing left because this was going to be covered again with fresh dirt. The CTX processor isn't the fastest, but I would think that it wouldnt have an issue with a Crotal bell or a Largie two inches in the ground UNLESS there were masking.

"Who knows what was in that 2" of dirt. It might be that other coil sizes wouldn't have found anything either."

I know, because I dug it. Nails and bits of iron everywhere. When I ran the two tone, it sounded like almost one continuous low grunt and I dug a quite a few items in the two inches.

"It might just have been getting that much closer to the target in bad ground and nothing to do with coil size."

The ground here in PA for the most is mild to near neutral. If I used a smaller coil, I may have got some of those other goodies.

I didn't believe it either until I experienced it so I understand everyone's point of view. If you don't believe it, that's fine.

 

[Treasure_Hunter]

If I ever come down to FL, please show me your hunted out spots

I don't believe in hunted out spots...

 

[ATwardo223]

Interesting read! i use the Explorer SE Pro and i always Feel as though i'm walking over deeper targets sometimes, even though the explorer and etrac are known for pulling deep coins. as for the masking i definitely think that the larger coil can be a hindrance. i am currently looking into a smaller coil to help to seperate some trash out of the parks
and other areas i search but does anyone else have any experience with the Etrac or Explorer SE with a smaller coil? generally i see people getting bigger coils not smaller. I believe all coils have a purpose but i generally dont see the smaller used much. what are your thoughts or experiences?

 

[b3y0nd3r]

Interesting read! i use the Explorer SE Pro and i always Feel as though i'm walking over deeper targets sometimes, even though the explorer and etrac are known for pulling deep coins. as for the masking i definitely think that the larger coil can be a hindrance. i am currently looking into a smaller coil to help to seperate some trash out of the parks
and other areas i search but does anyone else have any experience with the Etrac or Explorer SE with a smaller coil? generally i see people getting bigger coils not smaller. I believe all coils have a purpose but i generally dont see the smaller used much. what are your thoughts or experiences?

I had an etrac with the 6x8 excellorator coil and it was fantastic for unmasking(although currently, there are machines that are way faster than the etrac). It was a required coil in my arsenal of equipment. The depth was decent as well.

 

[cudamark]

Interesting read! i use the Explorer SE Pro and i always Feel as though i'm walking over deeper targets sometimes, even though the explorer and etrac are known for pulling deep coins. as for the masking i definitely think that the larger coil can be a hindrance. i am currently looking into a smaller coil to help to seperate some trash out of the parks
and other areas i search but does anyone else have any experience with the Etrac or Explorer SE with a smaller coil? generally i see people getting bigger coils not smaller. I believe all coils have a purpose but i generally dont see the smaller used much. what are your thoughts or experiences?

I have both the 3X5 NEL Snake coil and the Coiltek 5X10 Joey. Both do real well in trashy areas, but, you sacrifice some depth using them. I only use them in the worst areas, such as fire rings, picnic tables, benches, etc, or along rebarred walls, concrete walkways, and playground equipment.

 

[chefjuan]

Interesting read. I am planning on purchasing a bigger coil soon but not for purposes of depth but for purposes of area I can cover per sweep.

I too believe that recovery speed is one of the number one factors in fighting off target masking.

I know that I judge a signal by three factors. Repeatability, depth and signal strength. I often "unmask" targets by seeepibg over them, hearing what I would consider an "interesting" signal, and then narrowing my sweep, and giving it a 90 degree turn. Not all good targets respond well to this scrutiny but it helps you to determine if you have something good and bad. Also, I'll look at the depth reading and see how jumpy it is which usually signals multiple targets at varying depths. The only machine that I understand can actually identify multiple targets simultaneously is the 3030 which is a major reason I want one. Correct me if I'm wrong.




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[George (MN)]

I keep thinking not all places have an equal amount of trash, an equal amount of coins lost, equal mineralization, equal # of times they've been detected etc. So to make one rule for all locations may be less than perfect.

Also does one want to use their brain more while detecting than while doing anything else? Or do they want less thinking during detecting as that may make it more relaxing?

While Tom D. is a very smart person, he lives in an area where there is no ground mineralization. So the CZs are nearly perfect there. But how are they in areas of moderate or severe mineralization? I had a Fisher CZ-7 that I used for about 3 months and found more nails during that time than I did in 40 years of using dozens of other detectors.

I went on a vacation with a non-detectorist and got to detect 1 hour in a St. Pete, FL park grassy area. Got something like 16 coins w/almost no trash, including 4 nickels that IDed as nickels. But in MN, when CZ7 said nickel, it was never a nickel. So, poor ID is at least as big a problem as target masking, IMO of course.

 

[ATwardo223]

Thanks, i just may have to purchase the smaller coil then,

 

[IDXMonster]

Bey..did you find the final items with the stock coil,17" or the 06? I've been thinking about this same thing recently after striking out in areas where it doesn't make much sense that there wouldn't be good targets. Today...I'm going to turn my Gain down to 15 and run my Sens in Manual at levels just below instability. Usually I've run in Auto with the CTX but it's NOT good enough to get the deepest targets achievable by a particular coil. Auto is nice and smooth...but performance is cut to perhaps 60-75% of possible in a given area....that just being an educated estimate.
I'm thinking..."a fairground from 1865 that's been in continual use to this day and NO coins" Something else is going on here. I'm not sure the numbers are quite as high(or even close) to what are suggested in the article written by Tom but every area will having varying degrees of this problem,as George stated. Tom is an old hand at this as a lot of you guys are. All I can do is "trust,but verify". It may be that coins in my area are simply hard to come by.

 

[Jason in Enid]

everyone seems to be missing the differences in coils. the change in % that any coils sees is OLD info based on when concentric coils were the only thing around. Because a concentric is hot under the entire surface, the % change is a logarithmic function, which is why you get the "it sees 500% more ground" statements. While there are still lots of concentric coils in use there are also lots of DD configuration coils. Since they are not hot under the entire surface, the change in ground coverage is straight measure. A 6 inch coil has a 6 inch long "hot" strip, a 10 inch coil only sees 4 more inches. So instead of dealing with 500% more minerals and trash area, you only deal with about 60% more.

 

[IDXMonster]

everyone seems to be missing the differences in coils. the change in % that any coils sees is OLD info based on when concentric coils were the only thing around. Because a concentric is hot under the entire surface, the % change is a logarithmic function, which is why you get the "it sees 500% more ground" statements. While there are still lots of concentric coils in use there are also lots of DD configuration coils. Since they are not hot under the entire surface, the change in ground coverage is straight measure. A 6 inch coil has a 6 inch long "hot" strip, a 10 inch coil only sees 4 more inches. So instead of dealing with 500% more minerals and trash area, you only deal with about 60% more.

Jason,I think what he was saying is that 500% more COINS were in the ground and being masked,it wasn't necessarily about the volume of dirt. Besides,if the entire article was to be eaten lock stock and barrel...it would appear we indeed do have some really shitty machines. I just don't think that's the case.

 

[Jason in Enid]

Jason,I think what he was saying is that 500% more COINS were in the ground and being masked,it wasn't necessarily about the volume of dirt. Besides,if the entire article was to be eaten lock stock and barrel...it would appear we indeed do have some really shitty machines. I just don't think that's the case.

well, true, the 500% was talking about coins, but this quote ""If a 8" coil can 'see' a one gallon volume of dirt and the 11" coil (not 10.5") can 'see' 7 gallons of dirt at any given time, it is a fact that you are 7 times more likely to 'mask' a object with the larger coil, especially in trashy areas. It is so easy to get into trouble with the larger coil AND NEVER KNOW IT!" is the same concept.

 

[bigscoop]

Seems to me that this debate is in regards to perfect world environments, all of this being subject to the ground being hunted, which is for the most part never perfect. Regardless of coil type the processor has to work harder as these coils sizes are increased due to the increase of the size of the search field and the increase of information being sent back to the processor. As coil size continues to increase this can even effect the process of ground balance, etc., all of this then effecting things like the amount of acceptable sensitivity being applied, etc. At some point this processor is going to start filtering out those weaker returns as it begins to struggle to maintain stable ground balance, etc., which in turn can start to cost you deep and/or smaller targets, especially if the conductivity of those targets is already close to the mineralization in the ground being hunted. So I don't really think the information leading up to this debate can be applied to the ever-changing real world conditions that we hunt in.

 

[IDXMonster]

At any rate...here's a video from today using a huge coil in iron. Needless to say I was happy with the results!https://youtu.be/ib_F2QTe5HA

 

[b3y0nd3r]

I found the rest of those coins with the stock as I didn't have the 6" at the time.

Now, all I can say is this, I didn't believe the article either UNTIL I actually experienced it. The post is in regards to MY experiences, in conditions that are similar to Tom's. You may want to try an experiment, take a dime and dump a box of nails on it and see what happens. Everyone knows and it is common sense that a small coil will separate better than a larger one.