F19/g2/gb/trp Coil Compatibility Conundrum

[Noah (FL)]

I’ve always been interested in this platform, someday I’ll find one for the right price and jump on it.  With the talk of the new BountyHunter offering I was poking around reading posts and watching videos regarding these machines and stumbled across an odd one.  According to the First Texas coil chart this coil isn’t supposed to work with this platform, yet here is Bill from DirtFishing using the little 6” concentric elliptical for the F70/75 on the F19????  Anyone else have any experience with this??  He doesn’t show any steel bottle cap responses unfortunately but this could add to these machines ability for foil/jewelry hunting in those bottle cap ridden park/picnic areas    
 

 

[Jeff McClendon]

I experimented with the standard Greek Series 8" round concentric on my F19. It didn't fry it. It would not ground balance very well and detected very shallow only. Otherwise it worked okay. I can see how the little F70/75 elliptical concentric would be a good shallow coil in trash in discrimination mode. In All Metal, I doubt it would ground balance. A Nel Snake would be a much better choice for sure.

 

Jeff

[GB_Amateur]

6 hours ago, Jeff McClendon said:

I experimented with the standard Greek Series 8" round concentric on my F19. It didn't fry it. It would not ground balance very well and detected very shallow only.

I tried the Teknetics Greek Series (Omega, etc.) teardrop concentric on my Fisher Gold Bug Pro.  It worked on the first test (maybe 10 minutes) but the second time the detector started to squeal and scream.  On one of the other detector forums I found a thread involving Dave Johnson where he said concentrics wouldn't work on the Gold Bug family but then another poster claimed one did for him.  Dave backtracked saying that variations in components apparenly meant that they would work on some specific units.

I have a 6" round DD (hockey puck shape) Coiltek prototype which was made to work on some Fishers (F5?) and it works pretty well on my GB_Pro -- found a lot of coins with it.  But interestingly, similar to Jeff's experience, the ground balancing was at best inconsistent although it was quiet enough for my ground.

One other thing -- Dave Johnson has said that as coils get smaller, the difference in performance between concentric and DD becomes less.  So maybe Simon's and Jeff's suggestion of the Nel Snake / Cors Shrew would lead to the crown cap response you are looking for.  (Just a thought; have no idea if that is true.)

 

[Steve Herschbach]

You can run FT 13 kHz coils on 19 kHz models and vice versa, but results will be mixed. You may have ground balance issues, incorrect target id or other issues. You won’t hurt the detector by trying. My F75 6” elliptical concentric seemed to run fine on my Gold Bug Pro, basically same unit as F19. I also ran the 13” Ultimate from my F75 on the Gold Bug Pro. I’d not recommend buying the coils for the wrong machine, but if you have one already it can’t hurt to try.

Fisher / Teknetics 2018 Coil Compatibility Chart

Official Fisher Search Coil Page

Official Teknetics Search Coil Page

[Noah (FL)]

Thanks for the info fellas!!  
 

If I end up getting one a good friend has a CORS shrew(same as the snake) that he still has from his F44 that got stolen.   It’s almost a good reason to buy one🤔🤔😂😂😂😂

[GB_Amateur]

19 hours ago, Noah (FL) said:

If I end up getting one a good friend has a CORS shrew(same as the snake) that he still has from his F44 that got stolen.

The F44 operates at 7.69 kHz.  I wouldn't assume the CORS shrew made for that will work on a 19 kHz Gold Bug family detector, but it might.  I'm pretty sure the Teknetics Greek family (also 7.69 kHz) DD coils do work on the Gold Bugs so maybe it will be OK.  The table Steve posted shows different coils for the F44 and the Gold Bug but I don't know if that means they are actully different internally or if its just 'accounting'.

Another thing that can happen is that a coil works across models but not optimally.  CORS should be able to tell you if the Shrew for the F44 is the same as the one they sell for the Gold Bug family.  I do see that on their website they list the F44 and Gold Bug on the same line, so that's a good sign.

Lest we get too focused on detector operating frequency as the deciding factor, I note that coil compatibility is dependent upon more fundamental electronic properties of inductance and capacitance.  For example, the Teknetics T2 and Fisher F75 both operate at 13 kHz and were designed by the same team (may be some exceptions there).  They even look alike!  Internally they are quite different and in fact their coils are not cross-compatible.

First Texas does a pretty good job of making coils that work on different detectors.  I don't know if that is by intent or convenience, but it stands in contrast to some competitors who seem to go out of their way to force you to buy multiple sets of coils for very similar detectors.