My F70 is DEEP!!! Wow!

[sgoss66]

I spent several hours and set up a test garden today. I learned two things, in just a quick run through the garden with my F70 after I finished it.

1. The F70 is DEEP. It hits a 10" dime, and 12" quarter, and a 12" nickel (my deepest targets) with EASE, with the 10" stock elliptical concentric coil, zero disc, high sens/thresh, dE mode. It hits the coins hard, with room to spare (though it is IDing them all as iron, VDI number 13). But it hits them with ease.

2. In sL (slow) mode, this thing is EVEN BETTER. It is more susceptible to EMI in sL mode, but I have heard it said that sL mode on the F70 was a precursor to the Boost Process added to the F75/T2 LTD machines. Well, it's true, from what I saw today. On my 12" nickel/quarter, I could still hit them with a 2-3 inch "air gap," in dE mode. Switching to sL mode, I could easily increase the air gap to 4-6". Holding the coil at that 4-6" mark above the coin, and then switching back to dE mode, the coil would disappear. I had to drop the coil 2-4 inches closer to the ground to re-acquire the coin again. I tried this many times, to verify, as I was shocked. A 12" nickel or quarter, hitting easily with as much as a 6" air gap? WOW.

I also ran through it with the Gold Bug DP, but since we have a new forum for that, I'll not post about the Gold Bug results here in the F series forum!

Steve

 

[mudpuppy]

And the nickles will ping high along with the dimes and Q's and coppers...zincz ping low...I'll try that SL like you recommended ...dang, theres just so much this thing can do...I ran in Autotune most of last year, beach or field...and am just scratching the surface of the program capabilities..
I tell you , I think I learned something from that deep snow experience too...about the air gap being so great, and still hitting subsurface coins ..now I gotta go back to some of last years spots and try some of your settings.and with the coil a little higher, and faster, especially on the damp days.......thanks!

 

[Big Boys Hobbies]

Nice review Steve. Thanks!!!

 

[Wishful-thinker]

do the deep coins ping like iron?. try 3H

the 3H is what i use ,I really like it!

 

[sgoss66]

I don't think 3H is going to help in my case; all the deep coins in my test garden are IDing as VDI 13 (occasionally 12 or 14). Those tones are not high enough for the "H" part of 3H to call them a high tone. The "H" gives stuff in the nickel range a high tone, but my 12/13/14 VDIs are not in the nickel range, so they will still grunt, I'm pretty sure. I am hoping that at least a little bit of the issue is the newness of the garden (disturbed red-clay soil may be tending the IDs toward iron...) May need to get the 11" DD...

Steve

 

[mudpuppy]

Goss, OK, so deep coins come in on the iron range...got it...does your depth gauge give you an accurate reading? How about in AT? does this have any effect on the TID? Man I hate to think what I've been passing!
Hey Wishful, tell me what you think about that HH Pirate?

 

[sgoss66]

mudpuppy --

Don't take my "iron" readings as gospel just yet. First of all, the newness of the garden may be a part of the issue. I have a layer of topsoil in my yard (down to about 6" in my test garden), and then Oklahoma red clay (red due to iron oxide) below. When I dug the holes for my coins, and then filled them back in, obviously some of that red clay ended up at the top and middle of my hole. That is possibly some of the problem (with the soil now "disturbed," and the iron oxide-rich clay possibly throwing off the IDs). I need to do more testing; I did check depth readout on some of the coins; some were accurate, some of the deeper ones were off. Again, though, newness of the garden could be an issue there. I did not try it in all metal, but will check things out. Finally, I will check with the 5" DD coil, and maybe with my Gold Bug 11" DD coil, and see if that improves ID...and then post some results.

If the 5" coil ALSO gives all iron IDs, and once the garden settles and "ages" a bit, and the I STILL get iron IDs, then we may, as you say, be passing up alot of good stuff that is deeper, but which we think is just "iron!"

One last thought...I have gotten some better IDs on coins "in the field," while hunting. I recently ran my coil over an 8" silver quarter that an Etrac user had just located, and while the VDI numbers were a bit jumpy, they were all in the high range (70s and 80s) and I absolutely without question had enough VDI confidence to dig that target.

Steve

 

[Wishful-thinker]

Hey sgoss66 do you have buried nails in your test garden? if so whats their VDI? Imma thinkin that if they ID lower than the coins then that should be the setting
for your Disc, anything higher dig.

Hey Wishful, tell me what you think about that HH Pirate?

SHHHH! lol its kinda underated, not the best beach machine...but give me a shallow target area 8-10" infested with nails on land, Ill clean it for you.

 

[sgoss66]

I hear ya, Wishful-thinker. I don't have any nails by themselves; I have several nail/coin combination targets, to see how the coins ID near the nails. I will have to bury a rusty nail and check that out...

Steve