The 17" Xcoil Concentric Coil And Some Ad Hoc Comparisons To Axiom And GPX 6000

[Condor]

I bought the GPZ XCoil Concentric for my upcoming trip to Australia coming in mid September.  I wanted to put some run time on it so when Steve H suggested we take a short trip to Sawtooth to meet with forum member ABenson I jumped at the chance.  Steve H has an old patch that he has detected for over 10 years, I've detected it for over 6 years.  We generally find a few pickers but it really has been hunted to death.  The benefit of a hunted to death patch is there is no more trash, so any target stands a good chance of being the good yellow stuff.  

I ran the 17" Concentric as hot as the ground would bear, Normal, High Yield, Sens 17.  The ground has a lot of alkali salt, and the upper couple inches was damp from a recent rain so I added in the "Patch Find" setting to quiet the ground a little.  After a couple hours with no targets other than a few boot scrapes in hot ground, I got a good repeatable tone on the slope of an old push.  Since I'm new to the Concentric I had no idea what that signal was telling me.  If I had to guess from the tone, I would say under a gram nugget, 4 to 6 inches down.  So I marked the target and walked back to the truck to get my GPX 6000 and the new Coiltek 14x9 coil.  Steve H was nearby so we decided to check the target with the new Axiom.

We got there and neither the 6k nor the Axiom could hear the target.  I had to go back to the truck and get the Z to verify the target was where I had marked.  A clear and repeatable tone in both Normal and Difficult for the Z.  We pulled a couple inches off the top and started the whole process over.  The 6k gave a faint low tone over the target, but not something that would ordinarily stop me in prospecting mode.  In fact, I dig very few low tones in this ground because of the hot ground and hot rocks.   I'll defer to Steve H for his assessment of how the Axiom was doing over the same target.  

We did a lot more testing, and found a seam of hot red clay on the target, but to skip to the chase, we recovered a 4.6 gram nugget (4.7 on Steve's scale) at a minimum of 13 inches and probably closer to 14 inches.  

We reached a few preliminary conclusions on ground handling, raw detecting power and pricing of the 3 detectors, based on this one unscientific, ad hoc test with the detectors and coils we had available.  Our ideas on detector performance were severely challenged in some later completely unscientific tests.  More to come, Steve H is probably better suited to explain how things changed.  

[Condor]

[Condor]

Let me reiterate something about this "test".  We never set out to test anything.  We did this because the opportunity came upon us with an undug target in ground that had been thoroughly hunted.  We did this to satisfy our own curiosity and not to prove one detector or coil is better than any other.   We didn't have a stock Z coil, we didn't have a NF aftermarket coil, we had what we brought for an overnight hunt.  We should've or could've is simply not in this equation.  It is what it is your results may vary.   

[jasong]

Looking forward to you guy's thoughts. Good to see another one in use here in the US!

I love that coil myself, but it's a serious bear to use in the salt. 

[Condor]

8 minutes ago, jasong said:

Looking forward to you guy's thoughts. Good to see another one in use here in the US!

I love that coil myself, but it's a serious bear to use in the salt. 

Hey Jason,

We later detected the same area you had joined us for the 6k launch.  We had a short hard rain last night and that ground really got extreme in places.  I tried the Z in the Salt setting plus Difficult for the first time ever.  It quieted the ground, but struggled with a .3 gram test nugget.  Andy ran the new Coiltek 10x5 on the 6k and had no trouble with the salt.  It's always a toss-up, depth, sensitivity, or stability.  

[Gold Catcher]

Thanks for the report, Condor. No question the 17cc / GPZ is a powerful combination. However, I wager to say that the 12NF would have also picked up a 4 grammer 1 foot deep, without any problem I am pretty sure. The comparison with the quiet 6k (11 inch?) and Axiom is telling though. The GPZ is fantastic at depth and also has superb ground processing abilities.

GC

[Condor]

Teaser:  Further Testing

We reburied the 4.6 gram nugget and every detector coil combination disappointed.  I don't want to fuel the old "nugget halo" theory, but things changed for the worse for a reburied nugget.  I would have bet money that the 6k could easily find a 4.6 gram nugget at 10 inches.  Again, your results may vary, but I was quite surprised.  

[jasong]

I spent about 15 mins running the 17" spiral when we were there, and that was 15 minutes too long for me. ? Good test spot for equipment though, gnarly salt. 

I've wanted to try these CC's in NNV but just haven't had a chance to get back out since that trip I met up with you guys. Even in more mild salt here in the Rockies, I ended up having to switch to the 15" CC to reduce the salt response a bit. And even then, I usually just switch to the chirpy 6000 because it's still less noisy when the soil is wet. But when it's dry enough to use a CC, I've been pretty impressed. Curious to see your experience out there where it's even saltier than here. 

[Gold Catcher]

I am also curious how the 17cc performs in general/difficult. I have had several examples with the NF12 where general/difficult punched way deeper than HY/normal in highly minerlaized X laden grounds.

GC