Which coil should I buy, 10" concentric or 11" DD Fisher for my Discovery 3300

[kydigger]

I live in northern Ky. We have no problem here with mineralization. Its mostly limestone and top soil. I want to buy a bigger coil for farm fields ect. I've done a lot of reading on the net but still not sure which coil would be best. Ony openions would be appreciated. Thanks

 

[turtlefoot]

I have both and like both. There is a healthy price difference, with the 10" being cheaper. If Mother Nature allows, I plan on giving both coils a "head to head" workout this weekend to see if there is much difference in depth (although I doubt there will be). I like the sensitivity of the 11" DD coil and I like the wider field of view so to speak that it gives.

MY "head to head" is not going to be an air test or test garden. I have found what looks like an old cellar hole on a piece of property that I know has never been hit. I plan on hitting an area with the 10" coil in all metal mode. When I get a hit, I am going to change to the 11" coil and see if it picks up the signal. I am then going to hit the area with the 11" and do the same. I will then post the results.

BTW - I can pinpoint MUCH better with the 11" DD coil.

Doug

 

[Aces High 333]

Looking forward to your results. Have the same situation...

 

[kydigger]

Thanks, Turtlefoot. Look forward to your results.

 

[kydigger]

The main thing I'm thinking, based on what I have read, is that at depth the DD coil will provide longer front to rear coverage. It seems to me that that feature alone would make it the more efficiant tool for deeper coins an relics even in the best of soils. The wider coverage of a concentric coil wouldn't matter much, I wouldn't think, since your sweep will cover all of the ground under either coil.
You read often in the forums about a "better" detector finding coins another detector missed. Wouldn't it be more likely that those coins were simply skipped over due to the small search area concentric coils provide at depth.
Again, I'm looking for other opinions before I decide which coil to buy.

Thanks for all the help.

 

[turtlefoot]

That is the main reason that I purchased the 11" DD coil. I like the idea of the wider coverage at depth. I figured it would be more efficient and I could cover more ground quicker. I also figured that I would have a better chance of NOT missing something.

Two weeks ago, when I first tested that coil, I was swinging around a tree in an area that I had hit before. I found the brass from a 22 bullet. I have hit that area last summer with the 10" coil and I know that I swept over that area before. I know that the 10" coil will pick it up but I missed hitting the exact area. I have noticed that I actually get a signal from about 1/2" before the coil gets over a target to about 1/2" after the coil passes over the target front to back.

I hope I am being clear. I can set a dime on the ground and start swinging. As I approach the dime, it will beep approximately 1/2" before the coil actually covers the dime. I will get a signal through the entire length of the coil and it will beep to approximately 1/2" after the coil leaves the dime. I don't know if it will do that in the "real world". I do know though, when I get a signal, I start backing the coil up slowly and when I lose the beep, I dig at the tip of the coil and the target is there. I have hit the target 8-9 times out of 10 instead of the 6 out of ten with the 10" coil.

Mother Nature did not let me go out. Drizzle and rain all day. It is supposed to have a chance of rain tomorrow. Hopefully there will be a couple hour break in there somewhere. I have the camera all ready to go so everyone can actually see the difference between the coils.

Doug

 

[turtlefoot]

I didn't get a chance to do "head to head" last weekend. Maybe the weather will cooperate this weekend.

Doug