Built my test garden (finally)

I finally built it -- the garden is 10' x 10' square, divided into 2' x 2' squares -- for a total of 32 coin locations at each vertex (not counting the four outside corners where I buried shallow washers as markers.) The garden includes zinc pennies, copper pennies, nickels, clad dimes, clad quarters, silver dimes, and silver quarters -- at multiple depths ranging from 6" to 12". It also includes six "complex" targets (nails near, and on top of, pennies, dimes, and quarters. There are a total of 27 coins, plus five "empty" slots for future burials (plus the four washers at the four corners of the garden). I went over the whole garden and sanitized it with my F70 and removed all targets first (though I did not use a magnet as was suggested as being ideal).

My ground balances right around 60; a few interesting things I learned...

The F70 (10" elliptical concentric coil) will NOT ID a coin correctly in this garden, at this point. Period. None of them. All iron tones/VDIs. I'm hoping when it "matures," The F70 will get better IDs. The F70s favorite ID for all coins in this garden is, strangely, 13. The number 13 is for some reason a VERY consistent VDI for almost ALL the coins in this garden (aside from an occasional choppy high tone). The good news, though, is that the F70 will easily locate ALL of these coins. 10" dimes/pennies and 12" quarters/nickels are NO problem. Very consistent signal (though an iron tone) -- running high sens/high thresh. The F70 seems equally deep in disc. and all metal mode, and has depth to spare even on the deepest coins. I further learned that the F70s "slow" process is indeed similar to the boost mode in the F75/T2 LTD (as I had heard suggested before); it allowed me to see even the deeper coins with a substantial air gap; the deeper coins in default (dE) mode could only be seen with a 2-3" air gap; BUT in sL (slow), I could easily acquire even the 12" deep coins with 4" to as much as 6" of air gap. VERY surprising. However slow mode did very little if anything to improve VDI numbers.

With the Gold Bug DP, I noticed several things. One, this machine is substantially deeper in all metals mode than disc mode (unlike the F70). I could acquire 10" quarters and nickels in disc mode (barely), but 12" quarters were not audible. However, switching to all-metals mode, I could easily acquire 12" nickels and quarters (both modes were set at 99 sens.; I ran at 10 threshold in all metal mode to get an acceptable level of background hum). The ID system on this machine when in disc mode is MUCH better than the F70. I was able to get bouncy, but fairly consistent, high VDI nubers on coins even down to the deepest coins it could acquire in disc mode. I was pleasantly surprised that this machine could easily see 12" coins. The Bug Pro also did a great job IDing the coins in the coin/nail "complex" burials. I buried two pennies and two dimes at 6", one of each with a nail on top, and one of each with a nail 1" to the side of the coin; I did the same with two quarters, but at 8" (nail on top of one, nail 1" to the side of the other). When sweeping along the nail lengthwise, it was tough for the machine to get high VDI numbers; mostly iron numbers. However, on all targets, sweeping across the nail, the machine did a good job of IDing the coin. With the "coin next to nail" targets, sometimes it would only give a high VDI number when sweeping from the direction where it hit the coin first. Coming back from the other direction, it would sometimes only register the iron VDI. All targets with the nail on top gave high, but bouncy, VDI numbers, when sweeping across the nail (lengthwise, again, it was mostly iron VDI numbers).

I will bury some lead split shots for testing, and possibly a couple of 14" coins to see just how deep the F70 can hit a coin. I have little doubt it can do at least 14". It is one DEEP machine.

I have plenty of testing to do, but am really glad to have gotten this going. Thanks for motivating me, Brad!!

Steve



Edited 1 time(s). Last edit at 03/10/2011 01:28AM by steveg.

Good test bed... now run a hose and sprinkler on the bed to saturate your targets, then let it dry out a few days.

You'll then be very close to what you'll see years from now.

I have the same problem on coins with the F70. It ID's everything deeper than about 6" as a 13 when using the factory 10" concentric coil. When I put the 11" DD on it will ID much better and also hit a 13" nickel. If you can, test the 11" DD coil on the targets and see what you get for ID. You may also notice that the 11" coil will hit those targets even easier. I even drop the sensitivity to see how low I can go and still hit a 9" dime, a 10" quarter and an 11" nickel. I only have a few complex targets buried and they are shallow. I even have a few dimes buried either to the side of pulltabs or under pulltabs. The pulltabs ID as a nickel and on one of the complex targets all I get is a med tone from a tab. On the other complex target I get a high coin tone if I am approaching at the right angle. If I pinpoint center on the target it drops down to tab again.
I also find the G2/GoldBug very accurate on ID. You should be able to hear a nickel at about 11" with the GoldBug but it will only be a repeatable click or scratchy sound.

Tommy C.
(southernexplorer)
Deus - Etrac - GPX 5000

go-rebels: I'll run the hose/sprinklers on it as you say; appreciate the advice.

Tommy -- interesting that you also seem to get alot of "13" VDIs with that 10" stock coil. The only 11" DD coil I have is the one with my Gold Bug; I do have the 5" DD for the F70 which I haven't run through the bed yet; one thing I plan to test is the 5" F70 coil on the Gold Bug -- so per your information, I'll also test the 11" DD Gold Bug coil on the F70, and see what I come up with. I hope I don't have to buy two more coils (5" for the Bug and 11" for the F70!)

Also, your idea of some complex targets with pull tabs instead of nails is a good one, too. Mabye I need to add one more "row" to my garden.

I will try my 12" nickel again with the Gold Bug in disc mode. I know I hit it fine in all metal mode; I can't remember if I was able to get the 12" nickel but not the 12" quarter in disc mode, or if I couldn't get either. I only have a 10" and a 12" buried. I'm thinking I was able to get the 12" nickel but not the 12" quarter. I will verify tomorrow.

Thanks for the input, guys!

Steve

I cannot get a 12" quarter either with the G2 without a little cheating and it is still not a diggable signal.


The reason for the pulltabs around or above dimes is I had a target under the coil one day that was ID'ing dead on zinc penny and only a couple inches deep. Classic zinc cent target, but just to get it out of the way I stuck my Lesche just to the side of the target and popped it out and low and behold it was a standing liberty quarter just under a complete pulltab. It was one of the old ones with the beaver tail still in tact. After that happened I am always wondering what is under or next to all the pull tabs I can either hear or see while detecting. I find myself picking up the ones I see just hoping something is underneath it. If you just lay a quarter on top of the ground and then a tab on top you will see what I mean. The lower the tab reads by itself the lower it will pull the quarter, and dimes have a worse effect when low conductors are in close proximity so be careful what you walk over. One thing I have learned is when I get a multi tone from any machine I hunt with I instantly dig it. I find either multiple coins like nickel, dime or possibly zinc, quarter in the hole or even two different types of pulltabs.

Tommy C.
(southernexplorer)
Deus - Etrac - GPX 5000

That's some great info, Tommy. Great story about your standing liberty under the pull tab, and how the tab will pull the coin ID down...obviously in your case it pulled it down into the zinc range.

What do you mean exactly when you say "when I get a multi tone?" I struggle so much with iron falsing that it's hard for me NOT to get a "multi tone" on nearly every sweep when working iron-trashy sites.

Steve

Now I am going to make so many testing requests your going to send me hate mail

By multi-tone I am hearing a repeatable high and medium tone or maybe when set on a four tone setting I hear the highest tone and the next one down. It is never a iron tone in the mix just good upper tones. I will try and capture the sound on video and show you. When hunting in a tone mode you must be in tune with your machine when there is a lot of pulltabs and aluminum foil. Listening very carefully for the higher pitch signals between the lower ones. There are times when I am in the "Zone" and I can find many good coins in a trashy park but other times I find nothing. As I get lazy my finds will drop fast.
When I am beach hunting with a PI I am tuned in to the threshold hum listening for the slightest changes. A steady threshold in very important for me to get the deep targets.

Tommy C.
(southernexplorer)
Deus - Etrac - GPX 5000

Tommy --

Gotcha; I'd be interested in hearing multi-tones that you have experience are "good" tones...trying to find the "good" bouncy tones from the iron falses is tough...!

Terra --

No problem at all. I'll test whatever you wish...

Steve

Steve,

On my one test dime (clad at 6" in un-sanitized ground) I can hit it with my F70 with ID numbers that bounce around mostly in the high 60's and low 70's. The ID jumps around between Zinc, Dime and Quarter, more often Dime though. I am using the 11" DD coil, sen. 88, threshold -3, Speed DE and with 4 tones. If I am dead over the target I get a consistent high tone but if I am off to one side a little I will get a jumping back and forth between high and mid-tones.

That said though, while hunting an old house site on Sunday, I was able to get a good lock on a target that ID'ed as Zinc. This turned out to be a 1905 Indian Head penny. A couple of targets later I was able to get a reading that hit mostly on nickel though occasionally straying over to the tab side. This turned out to be a 1904 V nickel.

None of this is scientific though. On old house sites I dig everything that doesn't ID as iron.

Michael



Edited 1 time(s). Last edit at 03/10/2011 12:14AM by groundscanner.

Sounds like the 11" DD coil, at least in your ground, IDs a little better than my 10" concentric. I appreciate the info. I'll see if things ID any better after the bed is well-watered; if not, I may want to try the 11" DD -- I have heard it's a great coil for the F70, and what I've seen of it on my Gold Bug, I'm really liking it...

Steve

Steve..........if NONE of your coins ID as 'coin'; I would recommend burying a dime at 5" (and maybe even one at 4")........to teach WHAT depth targets start to drop off into the iron ID range. Yes, definately try the 11" DD coil for the F70. The tighter footprint handles bad dirt/minerals better.

I appreciate the advice, Mr. D, and I will do just that. I was thinking (please correct me if I'm wrong) that the coins (at least the shallower ones -- 6" pennies/dimes and 6-8" nickels/quarters) will ID a bit better with time in the garden -- maybe having disturbed the soil or whatever is throwing things off? I know in my ground, I have a bit more organic stuff in the soil down to about 6-8" in the garden, and then red sandy clay below that. Obviously, when filling the holes back in, I "messed up" this soil stratification -- with alot of that more iron-rich clay now mixed throughout the hole, instead of only at the bottom. One reason I thought this may be a factor, is that I know I have ID'd coins in the ground deeper than 6" on several occasions (locally, similar soil types). A couple of weeks back, I ID'd an 8" silver quarter as a definite coin; VDI numbers just a BIT jumpy so as to make me not certain to TYPE of coin, but definitely a coin. Just yesterday, my machine easily ID'd a 5" wheat penny as a penny. I know from other users' info that ID with this machine drops off and tends toward iron IDs with depth, but I did not think it would be at 6". Does the "newness" of the garden need to be considered as a factor in poor IDs? If so, then I'll wait a bit, water it, and see what happens. In any case, I will make another row or two on my garden and bury some shallower coins.

As far as coils, I have been using my Gold Bug with the 11" DD coil, and it is surprisingly good at IDing deep coins, as I mentioned. I wonder how much of this is to be credited to the coil, and how much to the machine itself? If I could get similar ID performance from my F70 as I am getting with the Gold Bug Pro just by switching coils, I'd do it in a heartbeat. Do you know which factor (coil or machine) might be making the difference in my Gold Bug Pro's ID superior ability (in the same test garden?)

I also have a 5" DD coil for the F70 that I'll try, and see about the ID numbers with it.

Steve

You read my mind..........5" DD coil testing Thanks.

TerraDigger --

Will be doing it soon, along with some NUGGET tests

Been too busy hunting the last couple of days. I'm learning the Gold Bug Pro, and really liking it...

Steve

Disturbed ground is a factor.............but such a minute' factor. A 11" elliptical DD coil is a MUCH greater delta. DO try the 5" DD coil.......but I do (moreso) recommend the 11" DD coil. Then................let me know what the results are.....and we'll go from there.

Thanks for the answer. Sounds like the "disturbed ground" is likely not the primary issue. I will try the 5" DD on the F70 in the test garden first. I will then try the 11" DD from the Gold Bug Pro on it next, though I suspect this is not an ideal coil match (crossing platforms). If the 5" F70 DD gives better VDI results (and especially if the Gold Bug 11" DD confirms in any way), then it looks like I may need to buy an 11" DD for the F70, to get better ID on deeper coins. Will I be likely to get similar depth of detection with the F70 11" DD as I'm getting with the stock 10" elliptical concentric?

Thanks,

Steve

I think you will get more depth with the 11" on the F70 in your soil.

MORE depth? If I get any more, I might start digging CHINESE coins...

Steve

You will see the ID on the F70 improve substantially with the 11" coil. The only downfall is that bottlecaps become a problem , but after you dig a few you will learn what they sound like. It took me a few(actually a bunch). I find the 5" coil lacking in depth or should I say ID in my ground, but as Mr. Tom D. says it might have a better affective depth when hunting really trashy areas.

Tommy C.
(southernexplorer)
Deus - Etrac - GPX 5000

Steve...........using a dime....you will acquire approx 1.5" greater depth with the 11" DD coil......vs........to stock elliptical concentric coil on the F70 (and F75).

Tommy --

Thanks for that info. I hooked up the Gold Bug Pro 11" DD today, and saw a BIT of improvement in ID on 6-8" coins in my test garden; I guessed that the F70 model 11" DD might do even better. You feel I will see a substantial improvement on ID with it, so I would like to at least test one in my ground. You sure make it sound like it might be worth getting one.

As for bottle caps, yeah, using the 11" DD on my Gold Bug Pro has shown me exactly what you refer to. I have dug several, and can't yet figure out how to discern a bottle cap from a coin. You don't have that problem with the concentric.

I also hooked up the 5" DD briefly in my test garden, and you are correct, I saw NO improvement on ID over the 10" concentric, even on the 6" coins. I know it has other strengths, but not on ID at any semblance of depth -- at least in my test garden.

Mr. D --

That's a pretty substantial improvement in depth. Wow. Thanks for that info. Even for the depth increase alone, it sounds like that 11" DD is worth testing. Might have to get me a backhoe, though, to dig some of this stuff up!

Steve

IMHO if your Gold Bug coil Ground Balances close to what the 10" F70 coil does you may not see much improvement.

Tommy C.
(southernexplorer)
Deus - Etrac - GPX 5000

You know, I forgot to ground balance that Gold Bug coil...I balanced with the 10" coil, then put on the GB 11", and didn't balance it.

Anyway, you say if the Gold Bug coil balances close to the 10" elliptical, I may not seem much improvement. But you still think I would see VDI improvement if I got the F70/75 11" DD? Further, would I assume from your statement that you would expect the F70/75 11" DD to ground balance differently than the 10" stock coil?

Steve

The dirt did not change...........so Grnd Bal should be fairly similar.

Quick Story and maybe you will understand afterwards. I had a 5" coil for my F75 and tried it on my G2 it was not very deep in my garden so I purchased a 5" Teknetics 5" coil and between the two of them they are almost identical performance on silver dimes. The performance you are getting with the Gold Bug 11" coil may be the best you can get overall. My ground balances at 61 on the F75 with one to two bars. My test garden is about a year old.

Tommy C.
(southernexplorer)
Deus - Etrac - GPX 5000

Sounds like we have similar ground conditions, and sounds like both the F75 coil and the G2 coil both performed about the same for you. I can't imagine that the 5" F70 coil's performance (it was AWFUL in disc mode) would be as good as you can get with a sniper coil for that machine...just doesn't make sense. Heck, they sell Gold Bug Pros with 5" DD coils as the "stock" coil...if those machines perform as poorly as my GB did with the 5" F70 coil, NO ONE would buy a GB Pro!

I will see if there is anyone that I can borrow an F70/75 11" DD to try on my F70, though. I'm intrigued by the possibility of better VDIs at depth with that coil.

Steve