could my 13" ultimate coil be bad?

[gunwolf]

yesterday was clean coils and detector day.. so this morning everything was fresh and I had all 3 coils with me, the stock 11", 13" ultimate, and 8x6 SEF...
I started the morning in a large open field that used to be a back yard , not to trashy started with the 13" , I ran manual sensitivity at 24 with good audible threshold..I was in a mostly open screen and in multi conductive. I went over a 25ft by 25 area and pulled a few memorials , a key and few brass pieces...nothing deeper than 4-5". after an hour I wanted to swing a bit lighter and have not used my stock coil in awhile so I changed out but kept the exact same settings... I went back over the area I just did with the 13" and coins just started popping out... I got my first buffalo at 6", and my second buffalo about 2 feet away at 8", a few clad quarters about 5" that the 13" did not pick up? so after re-gridding the 25x25 area again with the stock coil I came away with 1 merc, 4wheats, 2 buffalos, clad, a .30 carbine round, and few more interesting older things...the inside of a pocket watch and such...
so I bought this 13" used, and have not noticed till today but have not hit anything real deep with it... I have went deep with the stock coil...I even get 8" hits with the 8x6... so can a coil go bad? is there a way to test it somehow? thoughts? thanks

 

[cw3]

A lot of variables involved.

I would bury a coin in your yard and compare the 13" to the other coils you have. I have one Merc buried at 9" in my back yard. Its just for issues like this. I can check the coil to make sure everything is ok. I had issues with my 11" coil acting funny. Got home and it would not hit the 9" merc. no matter what it did. Normally it has no issues hitting it and giving good ID numbers.

 

[IDXMonster]

Agreed with above, in order to really know you have to establish a “constant”, and that is known items at known depth.

 

[gunwolf]

thanks guys...no test garden but next time out , I'll use the stock coil and find what i think is a good target , mark it and switch out the coils and check...

 

[WV62]

Just air test it on a coin and then do the same with your stock 11" coil the stock coil should be 1.5 to 2" less than the 13". So if they are close to the same you got problems with the 13" coil.

Ron in WV

 

[gunwolf]

Just air test it on a coin and then do the same with your stock 11" coil the stock coil should be 1.5 to 2" less than the 13". So if they are close to the same you got problems with the 13" coil.

Ron in WV

just did that and your right on about 1 1/2 to 1 3/4 shorter with the stock coil. soooo, coil is good, it has to be my soil, it is red dirt and red clay..so mineralization could be playing a part in this... the extra few inches of the Ultimate coil in this highly mineralized soil is killing it's depth? Kinda makes sense to me why the stock coil and 8x6 do better... so basically in the real world I'm not gaining any depth with the 13" over the stock coil, and even the stock coil is not going super deep...when I was in WNY we had sandy lume and dark earth... I dug IH's at 12" + with the stock coil, I can't push the sensitivity here I usually run about 20-24 with the stock coil while in auto +3 it hovers around 14-16. I guess I can hope for the occasional deep old coin.. other than that just keep on with what I'm doing. I have only found 1 silver quarter this year,they may have settled beyond my range... but a bunch of silver dimes 6" or less... and I'm over 65 wheats most at 4-6" a few were 8ish.. I am hunting some properties that date to the 1860's...

 

[5900_XL-1]

I bought and used the U13 for my Etrac and it never kept up in separation and detection, so it's dusty now. That one Detech coil just didn't match the 10x12, the 8x6. jm2c