Pupil2Prodigy
Junior Member
Read it here: http://www.dankowskidetectors.com/behindthemask.htm
Question: in general, larger coils miss what smaller coils are capable of detecting?
is the following statement true?
- Thread starter Pupil2Prodigy
- Start date
Read it here: http://www.dankowskidetectors.com/behindthemask.htm
Question: in general, larger coils miss what smaller coils are capable of detecting?
Grumpysrb
Forum Supporter
I can say the part about the large coil in a trashy area is true, from experience. Having multiple targets under the coil at one time can make it very difficult for the machine to determine which is which, and in the confusion mask.
However I have never, to my knowledge, had targets that masked to the point of giving no signal at all.
However I have never, to my knowledge, had targets that masked to the point of giving no signal at all.
Pupil2Prodigy
Junior Member
very helpful, thanks
I wonder though, is there a downside to larger coils in pristine areas free of trash (wilderness)
I wonder though, is there a downside to larger coils in pristine areas free of trash (wilderness)
graybeard
Elite Member
That is true, smaller coils can be pushed with higher settings. Larger coils mask lots of targets, that people don't know that are there. Just because someone uses a larger coil, and is satisfied with what they find, does not mean they found everything.
Never be afraid of smaller coils. You may be sacrificing depth and coverage, but in the trash and iron smaller coils sure have their place. Everyone out there would love to mount a 13 inch coil and zip through their hunting place considering it done when they hit the other side of the property. But in reality those of us that have gone over their favorite hunting places time and time again know how much we miss.
If you were using it in a literal wilderness, the downside may be the terrain you are hunting. You would have to deal with rocks, trees, etc. That may be easier to get around with a small coil.
Pick the right tool for the job... Most know you can't get by okay, using what you have on hand, might not work the best, but still works. My largest coil 12x10 concentric, is a monster. The weight changes the balance of my machine quite a bit, feel some strain. Had to shorten the shaft, swing is just inches from my toes, little ackward. Not the huge gain in depth I had hoped. Mostly use the stock coil. Switch to the small coil for tight areas with a lot of vegetation/landscaping, won't be going for depth anyway. Don't really do what I'd consider high trash, but there is usually plenty. I listen for interesting, or unusual signals among the trash. Sure, I dig a lot of trash, sometimes interesting trash, sometimes something good in the hole as well. I'll use the ID numbers on the screen, only if I need to limit the number of holes I'm digging. Just because you stuff that plug back in place, and you can't tell it's there, doesn't guaranty it's going to stay that way for a week or so, until the roots recover, if the do at all. We don't have good soil here, its pretty much beach sand.
Digger-Dave
Forum Supporter
100% Midnight!
You may give up some depth with a smaller coil, but the trade offs are few. All day long try to swing a heavy coil side ways on slopes up and over obstacles. It doesn't only get heavy, but keeps you out from getting inside brush.
I just installed my 5x8 on the AT Pro and it's awesome in thick woods.
Rawhide
Elite Member
I have the 15" inch coil for my F75.
The large coil does well, as coil wrap over comes a lot of targets. Now talking about coin sized targets, I do not believe masking is a problem for my F75. But you will hear everything if you set it up that way. The large coil losses some sensitivity to small items. The large coil allows me to cover a large area like a flat field faster and pin points just fine. I have not used the large coil for my AT Pro as the 5x8 has great target separation and I need that for some trashy hunts. So masking and separation for a large coil is minimal. Having a bum back and shoulder, the larger heavy coils are not a good fit for me. Here is a thought. Use your small coil for trashy hunts. Once you clear out the trash, use your large coil for deep targets. I have been taught to grid a area, go in layers. Go back on rainy days, hunt in the early am when the ground is cool. The gentleman who made the original post designed my detector. He is very good and if he says it, it is probably true. But my experiences are different than what Don posted.
The large coil does well, as coil wrap over comes a lot of targets. Now talking about coin sized targets, I do not believe masking is a problem for my F75. But you will hear everything if you set it up that way. The large coil losses some sensitivity to small items. The large coil allows me to cover a large area like a flat field faster and pin points just fine. I have not used the large coil for my AT Pro as the 5x8 has great target separation and I need that for some trashy hunts. So masking and separation for a large coil is minimal. Having a bum back and shoulder, the larger heavy coils are not a good fit for me. Here is a thought. Use your small coil for trashy hunts. Once you clear out the trash, use your large coil for deep targets. I have been taught to grid a area, go in layers. Go back on rainy days, hunt in the early am when the ground is cool. The gentleman who made the original post designed my detector. He is very good and if he says it, it is probably true. But my experiences are different than what Don posted.
My experience with a larger coil is that it is ONLY more beneficial than a regular coil on pristine/wilderness areas (or at least 'lightly trashed' areas). I've used large (12" or so) coils on a number of machines and have found that they do go a little deeper, but also are less accurate at pinpointing and id'ing targets. If you are out in the 'wilderness' hunting civil war relics, that's no problem at all - you are going to dig everything and the larger coil actually covers more ground and goes deeper. But you have to balance that against the increased weight - swinging a 12" all day can be tiring - and the size if you are in brush. My advice is to save your big coil for relic hunting. HOWEVER - I have to admit that my most memorable day(s) came hunting a large field in front of an old school with a large coil. In the '30s to the early '50s there had been a small grove of trees in one corner of the field, and it was where the band practiced marching (not in the grove - in the field!), and there were some basketball hoops (no concrete - just bare ground). I found that there was little trash and a LOT of good stuff in that field, and my large coil on a flat, mowed field was GREAT! I found more silver where that grove of trees had been than I have ever found before or since in one site. And I found two solid silver mouthpieces on the area where the band had practiced - one French horn, one trumpet. BTW - I knew where the grove, the practice field and the basketball goals were because I found an old yearbook from that school that had an aerial photo of the school grounds, so I knew what was where in 1954. Check out the old yearbooks - they can have lots of good information. Now it is just an open, empty field.
Vito
Elite Member
Yap, that is true. But...
to answer your question:
NO, larger coils won't miss the items smaller coils will detect. Alone the signal
from the bigger coil is not that clear as it will be from the smaller one.
And with that the detector can not separate that "single" target.
Double D's can help to do so depending on their windshield like footprint.
The bad thing is always more than one target in the "HOT" zone of the coil
by one sweep at the same time.
So, the larger the coil the bigger the chance. -vito
to answer your question:
NO, larger coils won't miss the items smaller coils will detect. Alone the signal
from the bigger coil is not that clear as it will be from the smaller one.
And with that the detector can not separate that "single" target.
Double D's can help to do so depending on their windshield like footprint.
The bad thing is always more than one target in the "HOT" zone of the coil
by one sweep at the same time.
So, the larger the coil the bigger the chance. -vito
Cherry Picker
Forum Supporter
Like Harvey posted, the right tool for the right job.
The key word in that sentence is "capable". Yes smaller coils are "capable" of getting targets larger coils can miss, but it depends on a lot of IF's. In general, small coils have the advantage in heavy trashy sites where having a small pattern is idea, but a larger coil will go deeper and cover more area giving you better odds. After all 90% is just getting your coil over the target. The larger the coil the better the odds are of getting over the target.
A good example is an experience I had with the CTX and the stock 11" coil vs the 17" coil. I had taken my CTX with the stock 11" coil to the park quite a few times and it was like with my E-Trac and stock 11" coil a hit and miss. If I got lucky and got my coil over a good target I'd have a keeper. In general I's spend an hour and maybe find 1-3 keepers. I got the 17" coil and the first 5 hunts to the park yielded a silver dime within 5 minutes of stepping in the park. Five times in a row my very first target when I just stepped foot in the par, and in area we had hunted hard, within 5 minutes I had a silver dime. A little too frequent to call it luck in my books.
In the end its all about the right coil for the right conditions. A big coil can be just as valuable a tool as a small coil.
The key word in that sentence is "capable". Yes smaller coils are "capable" of getting targets larger coils can miss, but it depends on a lot of IF's. In general, small coils have the advantage in heavy trashy sites where having a small pattern is idea, but a larger coil will go deeper and cover more area giving you better odds. After all 90% is just getting your coil over the target. The larger the coil the better the odds are of getting over the target.
A good example is an experience I had with the CTX and the stock 11" coil vs the 17" coil. I had taken my CTX with the stock 11" coil to the park quite a few times and it was like with my E-Trac and stock 11" coil a hit and miss. If I got lucky and got my coil over a good target I'd have a keeper. In general I's spend an hour and maybe find 1-3 keepers. I got the 17" coil and the first 5 hunts to the park yielded a silver dime within 5 minutes of stepping in the park. Five times in a row my very first target when I just stepped foot in the par, and in area we had hunted hard, within 5 minutes I had a silver dime. A little too frequent to call it luck in my books.
In the end its all about the right coil for the right conditions. A big coil can be just as valuable a tool as a small coil.
Porsche914
Elite Member
I'm still processing the dirt volumes of this post. I am picturing a 5 gallon bucket. Are we swinging this coil underground and counting what is both above and below the coil?
Porsche914
Elite Member
The math logic is all messed up in the example but the question and problem are legit. You can take a large coil to a recently demolished home site and will have trouble picking through all of the trash besides the fact you will loose your mind from all of the noise. If you use a smaller coil it will be much easier to isolate the targets.
My real world example of this happened earlier this year. I was headed to a friends house to look for a ring in a yard I have hunted (cleaned out) armed only with a super 12 coil. I encountered a group of club members hunting 3 lots where houses stood the day before so I joined them for about 15 minutes. It was impossible to hunt the trash with the large coil. I returned the next day with a sniper coil and made a lot of good finds right in the middle of the trash.
My real world example of this happened earlier this year. I was headed to a friends house to look for a ring in a yard I have hunted (cleaned out) armed only with a super 12 coil. I encountered a group of club members hunting 3 lots where houses stood the day before so I joined them for about 15 minutes. It was impossible to hunt the trash with the large coil. I returned the next day with a sniper coil and made a lot of good finds right in the middle of the trash.
pescadore
Elite Member
I have found numerous good targets with small coils in trashy areas that I know I would not have found with a larger coil due to masking. With that being said though, I always use the biggest coil I can get by with to get more depth. Using a small coil in large less trashy areas can get very frustrating due to the lack of coverage. I agree with the right tool for the job philosophy.
Rudy
Admin
I'd amend your question to: In general, larger coils miss what smaller coils are capable of detecting in a high density trash environment ?
And the answer is: In general, Yes.
There are so many factors involved that it is impossible to give a categorical answer. For example: Discrimination level used; concentric or DD coil; detector's receive side electronic design;....
nick hunter
Junior Member
A Tesoro Compadre would find much LESS gold if it was fitted with a 15" coil.
It would find deeper coins, tough.
One must not forget, besides that, that the larger the coil, the higher the ground noise.
So a larger coil on a detector with FIXED Gb is not a very good idea.
For instance, the 13" Ultimate on my Eurotek Pro did not produce any gain in depth.
The choice of an accessory coil must be part of a hunting strategy that not only suits your expectations, but that is also suitable for your detector, the areas you intend to hunt, and the targets you want to find.
Never forget that one of the best gold jewelry detector, the Compadre, has a small coil, a fixed GB and a fixed sensitivity.
HH
Nick
It would find deeper coins, tough.
One must not forget, besides that, that the larger the coil, the higher the ground noise.
So a larger coil on a detector with FIXED Gb is not a very good idea.
For instance, the 13" Ultimate on my Eurotek Pro did not produce any gain in depth.
The choice of an accessory coil must be part of a hunting strategy that not only suits your expectations, but that is also suitable for your detector, the areas you intend to hunt, and the targets you want to find.
Never forget that one of the best gold jewelry detector, the Compadre, has a small coil, a fixed GB and a fixed sensitivity.
HH
Nick
Beach hunting I do better with the 17". It hts on some real small stuff. Wouldn't hunt a trashy Florida park with one. You'd need a sod cutting machine
Rudy
Admin
Nick,
You raise a very interesting point that is often overlooked.
A larger coil produces a larger transmit field, capable of exciting a response from deeper targets. The transmit field is strongest below the coil's centerline, and weaker near the edges.
However, the response signal from a given size "low conductor" (like gold), is smaller than that of a "high conductor" (like a silver dime). So, a small gold item produces a smaller response field because the Eddy current induced by the transmit field are smaller (compared to an identically sized and placed silver object).
The detector won't register the target's response, until the target's field reaches the receive coil. Assuming that the response field is propagated from the target in all directions, the field's strength drops in proportion to the cube of the distance between the target and the receive coil. So, the larger the coil, the more distance there is from a target to the receive coil, unless the target is not directly underneath the coil's center; but then the target's response is smaller because it didn't get the maximum field from the transmit coil.
Somewhere between the coil being centered on the target and the coil's edge being over the target is the best combination of induced Eddy current on the target and distance to receive coil.
Moral of the story: A larger coil can be less sensitive to small low conductors and in order to be able to detect them at all with a large coil, you need to extensively overlap your sweeps.
Hope the above made sense.
Elad
Full Member
Yes it's true!
My first hand experience : I was hunting with a buddy and I came across a small target with my sniper coil. I told him to check it out with his detector, which had a standard 11" coil, and he told me it was iron and would not dig it. I dug it up and it was a .22 shell, which rang VERY clear on my machine.
I have also, while using my sniper coil, compared targets with other detectors using larger coils. I was always able to pick up any signal that the larger coils could. The people who were present during these tests were blown away, in fact.
I detect in the woods and the ground is always super busy at cellar holes ; I use my sniper coil a ton because of this.
I firmly believe that using huge coils is a waste of energy, and you will miss a lot of targets while using them. Of course, these results do VARY from detector to detector. For example, a detector using PI technology does in fact benefit from using larger coils, to find those deeper targets. When it comes to FBS or VLF machines it offers little or no advantage.
My first hand experience : I was hunting with a buddy and I came across a small target with my sniper coil. I told him to check it out with his detector, which had a standard 11" coil, and he told me it was iron and would not dig it. I dug it up and it was a .22 shell, which rang VERY clear on my machine.
I have also, while using my sniper coil, compared targets with other detectors using larger coils. I was always able to pick up any signal that the larger coils could. The people who were present during these tests were blown away, in fact.
I detect in the woods and the ground is always super busy at cellar holes ; I use my sniper coil a ton because of this.
I firmly believe that using huge coils is a waste of energy, and you will miss a lot of targets while using them. Of course, these results do VARY from detector to detector. For example, a detector using PI technology does in fact benefit from using larger coils, to find those deeper targets. When it comes to FBS or VLF machines it offers little or no advantage.
