Your smaller coil gives less depth - or maybe not

[BarberBill]

Recently read an article that made a lot of sense even though it was contrary to what most of us believer or have been told. It concerned actual working coil depth versus in air comparisons and even test garden comparisons. I'll try to condense the pertinent points here.

In more trashy areas, due to the multiple targets, larger coils often cannot readily deliver on their maximum depth whereas a smaller coil that isn't overwhelmed by the extra targets may still deliver its full potential or at least, more usable working depth.

In heavier mineralization one may get more depth from the smaller coil due to the fact that it's not reading as much ground interference and therefore can run with a bit more gain and again deliver more usable working depth.

I know from comparing the coils I own, that the normally accepted premise of the larger coils giving bit more depth versus smaller coils holds true in air tests. But these examples that consider true, working depth under different conditions are points worth considering and give another insight to how our detectors actually work.
BB

 

[WV62]

Good report, I I believe every word. This supports all the post about how well some are doing with the small coils.

Ron in WV

 

[Ron from Michigan]

Barber Bill,I agree that in field conditions smaller coils will excel larger ones ,depending on conditions.However there is a good balance ie too small, a 800 71/4 inch on a Sovereign has great performance exceeding larger coils for most conditions,but there can be too small, 5inch coils on this detector just don't give depth performance.My point there is a sweet spot on coil size for most detectors and some will be different.HH Ron

 

[Larry (IL)]

I wholeheartedly agree with your post but to go a bit further on the second point in heavier mineralization, I might bring into the picture the DD/SEF coils. They can be a larger coil for coverage yet have a smaller footprint (equal to a smaller coil) in design to better handle the mineralization and ground noise. In my ground a 10 inch DD/SEF will get more depth than a 10" concentric while in mild ground, the concentric will do better than the DD. This is one reason we get so many conflicting opinions on which coil is best when someone asks what they should use.

 

[BarberBill]

Well, there's a number of variables that can come into play here, but what I really liked about the article was the concept of thinking about usable, working depth. That's what really counts when we're out detecting.
BB

 

[Sailorman]

Well, I'm a bit new to all this but I am finding that many of the very trashy spots I hunt I'm getting better and at times deeper results from smaller coils. Maybe I'm not nuts after all?

While learning my E-Trac there were several spots driving me nuts until I put on a 5" Sunray and then everything seemed to come together. Better target ID and better depth in these areas.

On my AT-Pro the new 5x8 is now the coil that lives on it most of the time. I think it may be a tad less deep in perfect conditions but those are mighty rare around me and the smaller Garrett coil makes finds easier for me.

Nice info to have!

 

[BarberBill]

Sailorman, your comment on the 5X8 is similar to why many Whites users like the 6X10 as a most used coil. It separates well in trash and has decent coverage. Even though it isn't the deepest coil if depth is the main concern, it's deep enough for the majority of coin shooting etc.
BB

 

[WV62]

For my Fisher 1270 my 5x10 elliptical is on the machine at least 75% of the time and the 5" the rest of the time. The 5x10 runs pretty close to the same depth as the stock 8" with better coverage.

Ron in WV

 

[fowlercharles]

Hi BarberBill, You are absolutely right about the smaller coils. Another reliable example is the one reminding us of the bright lights/dim lights in dense fog, and we have all had that experience. HH, Charlie

 

[joe dirt_1]

I have found a smaller coil makes me slow down and be more thorough in my searching. My CZ5 with a 5 inch coil is as deep or maybe even deeper than the stock 8 inch coil. In a trashed out park the small coils will find many keepers that the stock coils may pass over without a beep


Roger

 

[Neil]

small coils are great but if you dont have one you can help your larger coil by lowering your sensititivy as needed, experiment and learn.

 

[slingshot]

The field is more intense and concentrated on a smaller coil for the "coin zone" in most situations. Back in the BFO days, I could take the "4 coil and pick up tiny rings,etc. that were missed by the larger coils. A good example is the Tracker IV. I had trouble in the tone mode with nickels-they just gave a quick "scratch" sound in the speaker and if I wasn't careful, I'd miss anything over 2" in the ground. Put on the 4" coil, and they sounded off like a large piece of foil.

 

[Canewrap]

I have a lot of new found respect for those people that hunt parks. I've been a relic hunter for the last 4 years and just recently tried hunting a park. How do you guys keep from going nuts, with the tons of trash? I found all of two zincolns, but dug about 20 trash targets (could have dug more but got tired of that real quick). I was using a small coil on my X-terra too.

 

[TerraDigger]

In my mineralized Idaho soil, the Omega 5" DD coil finds as many/more coins as the 11" DD for reasons already stated. I hunt worked over urban parks, homes and sidewalk grass strips. The 5" coil's depth is about 1-2" less than the 11" coil. It never ceases to amaze me the depth that little coil gets. I love the accuracy and co-located target separation.

 

[slingshot]

I have a lot of new found respect for those people that hunt parks. I've been a relic hunter for the last 4 years and just recently tried hunting a park. How do you guys keep from going nuts, with the tons of trash? I found all of two zincolns, but dug about 20 trash targets (could have dug more but got tired of that real quick). I was using a small coil on my X-terra too.

And thus the debate over ID versus beep=dig!

 

[Canewrap]

Well, in my opinion the TID vs beep-dig debate is principally because a lot of people only want one machine that can do it all. A heavy trash area is the perfect place for Target ID, but when you're not finding many good targets you'll have to thin out the trash to reduce masking. A beep-dig on the other hand is kind of unit you want when relic hunting or beach hunting since TID is kind of useless on real deep targets or when some of what you want to find is also iron. The mindset of using a TID vs a beep-dig is one of issues too. Its real hard to ignore a Target display and go only by sound when the area is trashy and you're tired of digging just trash, but if you have only a single tone to go by you'll dig more because to find anything you don't have much choice. Because of these differences I own one TID and one beep-dig and use them differently for the two different purposes mentioned.