NASA-Tom -- about that testing on my Gold Bug Pro...

NASA-Tom...

In discussions regarding unmasking, you have alluded several times to some "eye-opening" results that I will get, when I can set aside some time and test my Gold Bug Pro with the 5" coil. Well, I got my unit back from First Texas now, and I now have a 5" DD, 5x10" elliptical DD, and 11" DD coils, and want to do some testing, per your intriguing comments. I will do some air testing, and ALSO plan to do some test-garden testing (where I have coins of all denominations buried in 2" increments, from 6" to 12" deep)

Are there a couple of specific tests you wanted me to run with that 5" coil, or will it become obvious to me as I run through various scenarios? I have not tested the 5" OR the 5x10" coils yet, at all.

Having said that -- there is one unusual thing I recall when testing a 5" Fisher coil. Way back when I had an F-70, and did NOT have a 5" Gold Bug coil, for grins I took my F-70's 5" coil and I installed it on my Gold Bug. I just wanted to see what the 5" F-70 coil would do on the Gold Bug. I recall a MOST unusual finding. That coil, on the Bug, was VERY limited, depth-wise, in disc. mode. It could barely see a 6" coin. Not surprising to me. Wrong coil, and so I'd expect it to be incompatible with the discrimination circuit (that was my rationalization, anyway, be it right or wrong) BUT -- in ALL METALS mode, a highly surprising thing happened. That 5" F-70 coil attached to the Gold Bug was -- and I am not kidding -- DEEPER than the Gold Bug Pro's own 11" DD coil! I was hitting 12" quarter and a 12" nickel WITH EASE, in all-metals mode -- and even more solidly than I could with the Bug's own 11" DD coil. I just now went back and checked my notes, to verify that I am not mistaken on my memory. I don't know if this is at all related to what you are suggesting will be "eye-opening" when I test my 5" Gold Bug coil, but I guess I'll find out...

Steve

Wow steveg, would have been nice if that happened in disc mode,.....unusual depth plus separation from a small coil. You had to check your notes because it probably seemed like a dream. Very interesting..

Only compare the 5" DD with the 11" DD........... and at somewhat higher Sens settings.

Got it...I'll do some testing as soon as I have a little free time, and will report back...

Steve

Well, I did the first half of my testing -- the "test garden" part; haven't done the air testing yet.

I was running 100 gain in all my testing; ground grab around 58.1, and when in all-metals mode the threshold was run somewhere within a few digits either side of "zero;" when in disc. mode, I set the disc/tone break at 40.

The most surprising thing I found is sort of along the lines of what I mentioned before...the relatively meager ID-capable depth of the 5" coil, versus the 11".

First of all, today's testing confirmed something I had previously noted -- this machine is CLEARLY deeper, in all-metals mode, than in disc. mode. Interestingly, and surprisingly -- in all-metals mode, the 5" coil approaches the depth of the 11" coil -- the performance of these two coils is VERY CLOSE in all-metals mode.

HOWEVER, in disc. mode, the whole game changes. With the 5" coil, the only 6" coin that I would consider solidly acquired and fairly well ID'd was the nickel. The 6" clad/silver quarters were a close second. However, a 6" clad dime, silver dime, copper penny, and zinc penny were not slam dunks. I would get a tone on roughly 75-80% of the passes, with maybe 3/4 of the tones coming in above the tone break. Meanwhile, the 8" nickel was barely detectable, and the 8" dime, penny, and quarter (clad and silver) were essentially SILENT. Basically, this coil will not allow a confident dig decision a coin deeper than 6" or so, in disc. mode.

It's QUITE a different story however, with the 11" elliptical. The 8" nickel is easily acquired with "coin type" ID; the 10" nickel is soft, but consistent, with at least half of the numerical IDs above the tone break. The 12" is nearly silent. On the dimes, the 8" clad dime is "chirpy," not a clean target, but when I did get a tone, the numerical ID was, about 1/2 the time, above the tone break. The 8" silver dime is similarly inconsistent, but both these dimes stand a chance of being dug. The 10" dimes give an occasional chirp, but would be decidedly non-diggable. On the quarters...an 8" quarter -- silver or clad -- is a solidly diggable, fairly well-ID'd target. Both the 10" and 12" quarters give occasional chirps, but neither would I consider diggable.

Overall...while I do not have 9" clad or silver targets, the 8" coins were all solidly diggable, as was the 10" nickel. Based on today's testing, I'd say the 10" coil gives 3" additional detectable depth on clad and silver, and 4" more on a nickel, IN DISC MODE, as compared to the 5" coil. That is a substantial difference -- ESPECIALLY given that the 5" coil is very, very close to being capable of the SAME depth as the 11" coil in all-metals mode. Meanwhile, in all-metals mode, nearly ALL of my 12" deep coins have a chance of being dug...with EITHER coil.

Steve



Edited 5 time(s). Last edit at 01/29/2013 03:23AM by steveg.

Steve............ this is EXACTLY what I wanted you to see/witness. (and allow you to make intelligent detecting decisions basis/from)
Now.......... if only you could compare the F75 LTD or SE (in boost process) with 11" DD coil vs 5" DD coil. Or even a CZ with 8" vs 5" coil. There's very minimal loss of depth in ID mode....... when using the 5" coils.
Not so///Not true with the Gold Bug SE.

NASA-Tom --

Thanks for encouraging me to do that testing. I can see that I have some issues here -- I can see where this could be a GOOD machine for hunting in iron, and with the 11" coil, I get acceptable depth. However, if I want to use the smaller coil, I'm very limited.

I LOVE how quiet and stable the Gold Bug runs; I like the audio, it's intuitive and easy to understand. It's FAST; I like the variable tone break (I would LOVE this machine to have ONE MORE tone break assignable -- the "low" one to be set at the ferrous/non-ferrous boundary, and another which you could set at some "gold/silver" break point -- i.e. to separate mid tones from "coin tones"). BUT -- even without this, I really click with the Gold Bug. But -- for my relic hunts, I would like this same type of platform but with more power/depth.

So, what to do?

I know the F75 with boost is a powerful, deep unit, and I know you have noted that this machine with the 5" coil is capable of very impressive depth. But, I'm just not sure this would be an improvement in my soil. I had an F70, and it did NOT perform in my dirt...

The issues with the Fisher units, for me, are three-fold. ONE -- my F70 was SUPER chattery. Drove me nuts. That's one reason I like the GB Pro so much -- it's SUPER stable. TWO -- I don't like the tones. I really prefer the information contained in modulated VCO audio, as on the GB Pro, versus just a "beep." THREE -- and this is the BIGGEST one -- the F70 (while not a boost unit) did NOT give me any better ID at depth. I had the 5" DD coil, and -- though I am going from memory, it did NOT exceed the performance of the GB Pro's 5" coil, in my soil, in terms of ID. The stock 10" elliptical was no better. THAT was the biggest reason I got rid of it -- beyond the instability/chattiness and the audio. I simply could not get reliable ID beyond that 6-ish inch mark. That F70 was a depth BEAST. Twelve inch coins were a breeze; in sL mode (the boost process "precursor" as I understood it to be), I could hit the 12" coins EVEN WHILE RUNNING 3-4" AIR GAP. BUT -- starting about 6" deep, and DECIDEDLY SO beyond 7-8", all coins ID'd as iron. I ran a CZ through my test garden. SAME THING. Fisher units (all that I've tested) are simply brought to their knees, ID-wise, starting at 6", in my soil. The Gold Bug Pro has been the BEST of the bunch, the F-70 would have been second -- at least judging by the one day of testing I did with a borrowed 11" DD coil. With this coil, it may have come close to the GB Pro with 11" DD. BUT -- a 5" DD, or ANY size concentric coil on a Fisher unit will start struggling around 6". With an 11" DD, I can extend that ID depth another 2-3". I just don't understand how these units can hit 12"-plus coins solidly, and YET only be able to give decent ID through roughly HALF that depth.

From some that I've read, a Vista Gold might do most of what I want a machine to do. It's deep and fast, and I think has adjustable iron/non-iron tone break. HOWEVER, as I understand it, there is NO ID capability with these units, aside from an iron/non-iron. If that's the case, then it would seem not to be that much of an improvement over what I have -- I can probably accomplish similar depth with my GB Pro in all-metals mode. I would have the iron/non-iron audio with the Gold, so SOME ID capability with depth as compared to all-metals mode on the GB Pro...which is a plus...

Any thoughts on this? Perhaps a new Fisher unit that is purportedly being designed might do what I need it to in my soil...

Steve

Steve,

Your soil/mineralization is causing your ID to rapidly drop off at 6" and greater. A gold prospecting unit is much better designed (in general)..... to handle bad dirt.........as....that is where most gold is found.
Have you (can you) "try" a GMP or Deus in your soil....... especially your test-garden? These units are tone ID...... with a 'coin tone' conductive range. Never mind the fact that these units are only single-freq units....... as they defy some basic physics principles.
I don't believe the Deep Tech series units have more than two tones......... which are specific to ferrous vs non-ferrous. (No 'coin' conductive tone).

NASA-Tom --

I actually do have a friend with a Deus; I may be able to get it from him and run it through my test garden -- but have heard others say that their ID suffers with depth also. I'd like to see how it handles my ground. I would love to run the GMP, but don't know anyone that has one...and I'd love to run the Vista Gold. The only other unit that I would like to try is the AT Pro (or AT Gold), to see if they handle things any better...

Right now, though, the 11" DD on my Gold Bug Pro will do an "acceptable" job; the problem is that I'll just struggle in dense iron without small coil ability. Yesterday, I dug an old fired/deformed .22 cal bullet in my yard with the 11" DD on the GB, about 30 feet from my test garden; it was about 9" deep, and was giving decent-enough ID that I knew it was a non-ferrous target. I was impressed to have hit that target, with decent ID, at that depth. I SHOULD have grabbed the 5" coil and tried to hit it, but I didn't...but I'm fairly certain it would not have acquired the target.

Steve

Steve,

I have a GMP that I would send you to test; HOWEVER (yes..... you guessed it!!!)...... it is the dead-of-winter in Florida,,,,,,,, the time that I inland hunt........... as grass is not as thick/fat/swollen/tall/tropical. And I have 2 others (that are overdue) for analyzing/testing this GMP.

NASA-Tom -- a very kind and mighty-fine thought on your part, and I really appreciate it. I understand, on the inland hunting time! If there ever comes a time that your machine will sit idle for awhile, and you'd be willing to send it my way, I'd jump at the opportunity!

Steve