F70 stock 10" elliptical concentric vs. the optional 11" DD

[mudpuppy]

Welcome tsecor68!

All I have is the 11"...that said, I got the rig 4yrs ago April, didnt know a thing, bought it on advice from a local detector shop...got it with the 10 too, but never used it..the old guy told me the 11 really soups up the 70 performance...it probably does, but what did I know? I guess he thought I was going to be hunting old silver, which I dont, (but could if I wanted to) so...I got really good with just the 11, and sold the 10 on here to a Forum member since I never used it...

Now, it all depends on what kind of hunting you like to do and your locations...the 70 has enough adjustments on it that you can effectively hunt just about anywhere with any coil! If you use what you got for a while, and not worry too much about coils, you will see...find some real trashy locations, and pick your way through them with it...find some wide open clear and hunt on through it...get into some totlots and hunt right on through them...pretty soon, you will get comfortable with the settings and tones and all that, and that 10 will be a killer in your hands for just about everything.

About the only other coil I'd like to try is the 5"...just on account of a lot of feedback here of what it can do, it takes just a little while to get comfortable with the 70, you have to start out easy and find a set up that you are comfortable and confident with...the 70 is a fast rig, so if you got a big park or schoolyard closeby, get in there and start your education! We here have plenty of advice and support!
Mud

 

[REVIER]

tsecor68,

The standard coil is fantastic, I found silver on my very first hunt with the F70 and this coil, gold with this setup a few hunts later in a total trash pit because like on most other Fisher units the targets separation and rapid recovery abilities on the F70 are superb.
In areas with a huge amount of bottle caps this is my go-to coil, very fast and efficient to figure these out and that coil still gets very deep depending on your settings.
The 11" is a wonder, more depth than the 10", (I am reaching the 15" level in my great soil), with more info on the screen on the really deep ones although in those cases you really gotta go with the tones and forget what you see on the screen.
If you turn the sense way down using the 11" the F70 seems to turn into a pretty precise surgical instrument, the scanning field appears to shrink and has the effect of changing to something like a sniper coil in the way it works while still getting great depth.
I have have been using this technique, (thanks to the recommendation of mudpuppy and others), to find great targets in total trash pits and it is effective and effortless.
The bottle cap thing is not so bad using this coil either, by rimming the target and seeing most of them drop down to lower numbers even to iron, which good targets like coins won't do, I can usually get a handle on these things about 98% of the time...but the standard elliptical is just a bit faster and more efficient for me to use in situations and sites with massive amounts of these things.
I also have the 5" DD sniper and from what I am reading also a coil that can be miraculous in the way it works and the depths it can reach, but I will not even start experimenting with that one till I get my fill of playing around with the 11" dd which will take awhile.

If you only have one extra coil to choose from at this time my vote would be go for the 11" DD.
Massive depth and and to me sometimes almost unbelievable and accurate info on targets at those depths while also having the ability to hunt high volume trash packed sites if you don't happen to have the sniper or like me are too lazy to change over to it in the middle of a hunt even if you do.

Trust me, the F70 with any coil will find you enough to buy a full compliment of additional coils for this thing in pretty short order if you learn what it can really do.

 

[Rainyday101]

Very interesting read here. I am going to buy an F70 this spring and have been debating on which coil. My ground is really mild so I am thinking about going with the stock 10". From what I have read from Dave Johnson and Tesoro, a concentric will always be deeper in mild ground with little to no mineralization.

Tabman has me looking and thinking of getting that NEL Sharpshooter as a the secound coil.

 

[knarfj]

Great subject! I was looking for similar input in an earlier post but it got closed. http://www.findmall.com/read.php?37,2027906,2027906#msg-2027906

I have since purchased a 5 inch DD coil for my F5 and it's the cats meow in trashy areas. To compare a like 5 inch sniper coil, or any other coil for that matter with any other, give this nail test at the "American Heritage Research & Preservation Society" a try. http://ahrps.org/tipsandtechniques.php.

I found it a very good demonstration on how ferrous items such as nails and I would assume other items that have been discriminated out can mask desirable targets.

HH

 

[REVIER]

Very interesting read here. I am going to buy an F70 this spring and have been debating on which coil. My ground is really mild so I am thinking about going with the stock 10". From what I have read from Dave Johnson and Tesoro, a concentric will always be deeper in mild ground with little to no mineralization.

Tabman has me looking and thinking of getting that NEL Sharpshooter as a the secound coil.

Yes, that is true.
Concentrics will usually be a bit deeper than DD's, if we are counting the pure depth of the scanning field which in the case of this 10" is probably the size of a quarter at the limit.
However...and don't ask me why, but in my great soil the 11" DD is deeper....WAAAAY DEEPER.
Most say average is 2" deeper using this coil but I think I am getting way more than that.

At 10" I can get a solid audio hit using the 10" coil but no info on the screen which will happen when a target is near the end of the scanning field.
The 11" coil gives me the audio tone, AND screen info at 12 and 13", and one target which was a bit jumpy but the VDI did show me the correct numbers more often than false ones on this thing that turned out to be 15" in depth.
I don't always get screen info on stuff that deep but on that one I did and it repeated.

 

[dbax]

Wow, REVIER, what kind of digging tool are you using, a shovel or back hoe -- great depth I have the 11" DD and a smaller
NEL sharpshooter. On the one hand I wish I could get the depths you are getting then on the other I'm glad I don't as the
dig would be way too serious for me. Of course Rocket man has a method with the blanket and shovel but I decided I did
not want to get on the evening news.
What are your settings anyway -- in my soil the digging is easy most of the time around the parks but going that deep
would take some serious digging tools and I think the parks patrol would kick me out. My deepest find in the park was an
old flat and very rusty bottle cap down about 8". I did find a couple of walking silver halves, a week apart both at around
6-7". At the Lake the dried dirt is like concrete and I would need a jack hammer to dig past 6".

In air testing I can only get a silver quarter at 9-10" but in actual dirt it seems to be only about 8". I'm wondering if maybe
I should send my machine in? I have the same set up you have, the F70 with 11" DD coil. Let me know what your settings are
and I will set my machine up the same to test it. Thanks, Dan

 

[mudpuppy]

Well said Dan!...this is an old thread...I remember it from when I first started...SGoss was running hot and looking for deep silver and help...he was a serious deep silver hunter, and got frustrated pretty quickly with the 70 set up hot, got rid of it, and went another route...hes still hunting, just not with the 70...Back then, there was little to go on regarding setting the thing up and we all had to learn on our own, I was too new to the sport to offer any help to him, and he got ME second guessing my purchase, but I was too dumb to know any better and just bucked it out...

The 70 is a surgical implement, I think REVIER made mention of a few weeks back?, and thats the best way to think of it, its so precise and fast, that it can easily scramble a newbie brain, or even somebody that has experience with other rigs... yet, if a guy commits himself to mastering it...indeed a surgical implement!...REVIER has a very fast recover method, and vids to show how he does it...which may prove helpful to readers here.
With a fast rig, you need a fast retrieval to maximize its strengths per outing..

Anyway, I think we will be constantly trying to align new users of the 70 advising a light run until they are aware of what they got with this rig, and that takes some time..all in all, its a heater..the extent of its capabilities yet unrealized... If I can get a few to try coil hopping, you will wet yourself bloody stupid...still no takers? Oh well, all the more for ME!

Mud

 

[REVIER]

Wow, REVIER, what kind of digging tool are you using, a shovel or back hoe -- great depth

Got it on sale at Harbor Freight...used a 25% off coupon, too!
It took awhile for me and 3 other employees to wrestle this thing down from the top shelf.

 

[dbax]

Hilarious I knew you had a secret weapon -- where can I get one of those -- Next I will have to upgrade my utility belt.
You made my day, even my wife laughed out loud.
I went out this morning in the rain and followed your advice and listened a little harder and dug up some quarters giving an
on again off again signal one was at least 9" soft loss dirt around some trees. I'm thinking these were mostly on edge, found 12
in all and in an area I had hunted before. Okay, I admit, I set the SENS up to 80 so, thanks for getting me to concentrate a little
more -- sometimes I think a fella starts treating his second love (F70) like the wife and tunes them out -- looking around making sure
the little woman is not reading over my shoulder, if you know what I mean Peace brother, and thanks for the update --
Harbor Freight, you say?

 

[REVIER]

Wow, REVIER, what kind of digging tool are you using, a shovel or back hoe -- great depth I have the 11" DD and a smaller
NEL sharpshooter. On the one hand I wish I could get the depths you are getting then on the other I'm glad I don't as the
dig would be way too serious for me. Of course Rocket man has a method with the blanket and shovel but I decided I did
not want to get on the evening news.
What are your settings anyway -- in my soil the digging is easy most of the time around the parks but going that deep
would take some serious digging tools and I think the parks patrol would kick me out. My deepest find in the park was an
old flat and very rusty bottle cap down about 8". I did find a couple of walking silver halves, a week apart both at around
6-7". At the Lake the dried dirt is like concrete and I would need a jack hammer to dig past 6".

In air testing I can only get a silver quarter at 9-10" but in actual dirt it seems to be only about 8". I'm wondering if maybe
I should send my machine in? I have the same set up you have, the F70 with 11" DD coil. Let me know what your settings are
and I will set my machine up the same to test it. Thanks, Dan

I have never done air testing with this one.
Too much wifi in my place and never great results, but from the minute I started swinging this thing I got a very eye opening idea of the depth.
My soil is unusually good.
Probably good karma coming back from hunting for 2 years in probably the worst soil in the country where NO DETECTORS got more than 4-5" in the worst of that stuff which covered about 90% or more of all sites.
As you can probably surmise, after going from that environment to dirt where I am reaching these almost unbelievable depths I feel I am in heaven.

I usually GB in the low 40's to the mid 50's with only one bar on the dirt meter...if that.
Using the 11" DD coil I just recently I got a solid repeatable hit on a dime at a measured 5" on 19 sense, 0 thresh, 4 disc but it was the same at 25, 4H tones and all tones worked fine, SL speed.
DE speed worked the same at the same exact settings but the tone in 4H was strange, like 1/2 the tonal qualities were gone but it was still solid and repeatable.
Switching to SL brought everything back to a full and rich sound.
On that target raising the sense to 30 added 2 inches, to 40 2 more inches, 50 2 inches more with 5" in the dirt and 6" in the air.
That was all I needed to see and I stopped testing after my jaw dropped a bit.

In other areas I easily reached 8" on an Indian Head cent spill in an area with extremely unusual EMI at 80 sense, DE, -1 on the thresh, 4H tones then checked with 1F, disc I believe was at 4 but it might have been in the mid 20's due to a ton of foil and can slaw trash in the area..
Jumpy signal from zinc to the copper area, caused by the 3 IH's and one 1915 wheatie laying spread out over about a square foot area so I thought I was going to dig some junk, but the tone was excellent and that always triggers my instinct to dig first and foremost
I didn't play with that one, wish I did, but I think I might have been able to hit this thing at less sense...maybe a lot less sense.

Another time, at about the same 80 sense settings and -1 or -2 thresh and DE using the standard concentric coil I hit a beaver tail tab at 10".
A few flashes of very high numbers on the screen like a dime, and then every pass after that the screen went totally blank with no other info forthcoming.
I walked around this thing and hit it from at least 3 angles and every blessed time I god a solid, repeatable dig me please high tone.
Got me curious so I dug it.
Weird that the tone and initial numbers were so off, but pleased there was something down there every bit of 10" in depth exactly in the center of my hole after I pinpointed.
If You read Rocket Tom's stuff, he says targets at depth will usually not trigger the screen to react and the areas it tones might be off, but in cases like that it is all about the SOLID sounding tone and pay no attention to what you see on the screen, anyway.
Coming from hundreds of hours using Tesoro's this was an easy lesson to learn and understand and it is now ingrained in my DNA.
I now actively look for signals that have a tone and don't make the screen react at all.

With the 11" DD coil back on, and by then practicing hunting with maxed out settings in both disc and AT trying to notice good targets in the million tones and fast changing numbers on the screen, I came across a target at 15" that repeated and was solid in the tone again from multiple angles.
This time, even though past 12" there is not supposed to be any screen info, I did have numbers pop up on every pass from the low 20's to about the high 30's, maybe a little higher.
Numbers from 23-25 were the most common numbers I saw even though there was a decent amount of jumping.
The target was a thumb ringer off an old time bicycle bell and the actual numbers on that target were 24-25 out of the ground.
All of these deep targets were dug out of slightly moist soil due to it being right after a few warmer days that defrosted the frozen soil, but it wasn't wet dirt at all and down deep past 4-5" or so the soil was absolutely dry.

Air testing is usually less than dirt depth so that sounds normal to me, but I don't really know what air testing results would be for me to compare to yours.
I will try to remember to do this next time I am out in the field and get back to you.
I know the problems you had at the beginning and would hate to see you send it in again for no reason.
For most, 8" is pretty good depth if their soil is less than perfect.

As far as a digger, I am cleaning some clad as we speak and I am ordering a new hand digger.
I love my Lesche, but I not only like to move fast and efficiently in digging shallow targets 6" or less which I have learned to do with a ton of practice, I would like to learn to do this on really deep targets also and my flat bladed Lesche is not the right tool for doing that in the relatively small holes I would prefer to open.
Before I moved here I was talking to a few people that lived in the area and they were telling me how great the soil was.
On guy said the dirt was so good that it only took 10 minutes to dig a 10-12" deep hole and I was stunned.
Volume is my thing and 10 minutes to dig even that deep would kill me if that was my time on every one in a hole without obstructions like big roots so it is time to change to a new kind of digger that will hold up to the punishment I can dish out but also can scoop out the dirt at a rate I can be happy with.
This is what I ordering soon, and expect my digging time on deep holes will greatly improve with a bit of practice and in my great dirt I should have plenty of opportunities to do just that.

 

[WhatTheBeep]

In air testing I can only get a silver quarter at 9-10" but in actual dirt it seems to be only about 8". I'm wondering if maybe
I should send my machine in? I have the same set up you have, the F70 with the 11" DD coil. Let me know what your settings are
and I will set my machine up the same to test it. Thanks, Dan

Hi Dbax. I got the F70 about two weeks ago with only the 11"DD coil (it actually says "F70" on the coil though I doubt there's a difference between it and the F75 11" DD?) and I haven't had nearly as much time as I would like to play with it. However, I spent a few minutes doing air tests with a clad dime and a yardstick a few days ago with some noticeable EMI present from a nearby power line. With 3 tones, Disc 6, Sens 99, and SL speed I was able to get consistently repeatable high tones at 11.5". In AT mode, Sens 99, and SL speed the "depth" jumped up to over 14", but then it became hard to tell the difference between the dime audio and the EMI noise, but it got 14" at least consistently. I can't recall if Thresh was at -3 or -2 during all my tests, but it was one of these to try to quiet the EMI chatter some. Not sure what the numbers on the screen were as I couldn't see them from the bottom of the coil. Also, these were with pretty fast sweep speeds. But I believe you should be getting more depth out of a silver quarter in an air test than my dime unless you were in some really heavy EMI or if our settings were pretty different.

Wish I could tell you I'd gotten 12" on a coin in the ground, but so far the deepest I've gotten was about 5".

 

[dbax]

Hey, Whatthebeep, thanks for the input -- the F70 and F75 coils are all interchangeable, but only between these two. I hear you brother, like Revier
you guys are metal heads for sure. In my area I cannot run my machine at those levels, way too much chatter. Some of the parks I search are old and filled with trash and if I ran the settings
you tired out I would go crazy. I already have tinnitus. Soil conditions will dictate, but if you get yourself a tool like Revier, well, anything is possible

Air testing is good to get a handle on your readings, set up a couple of mirrors to see your numbers or get a longer arm, or shorten the coil shaft and lay the coil
back then you can see the screen and swing the coins. I tried the NOTCHING out and it worked great in my air tests. I notched out iron and it would not
read a nail at all, great, right? I then took a quarter and held it with the nail and it signaled a strong quarter hit. Next I tried a tab and again success, the tab would
read, wonderful but the quarter and dime and silver ring sang out loud and clear all the way down to 9", fabulous, anything deeper than that is another story, or another
type of searching. So, with all of this good knowledge I go into the field and dug up a couple of nails -- nails? They were wet and very, very rusted. Then I hit some great
nickel hits, but turned out to be bits of aluminum -- I am finding thing, but the dreaded Bottle Cap, be ready to dig some of those. Fewer tabs but still, in the ground, when moist
they will read when they will not read in an air test. So, just saying, if you know what I mean, so don't get confused when you go our in the field -- nothing wrong with your
machine if you find you are getting hits on things the air test did not read. Now, in my area, if I were to set up a hot, hot machine, I am sure I would get deeper hits for
sure, but I do not carry a shovel and the constant blipping, popping, snapping, crackle and chirps from all of the junk and other things just make me go insane.

 

[REVIER]

Now, in my area, if I were to set up a hot, hot machine, I am sure I would get deeper hits for
sure, but I do not carry a shovel and the constant blipping, popping, snapping, crackle and chirps from all of the junk and other things just make me go insane.

AHHH, there's the difference.
I was already so close to insane you couldn't measure it, so all this crazy, jumpy, huge amount of info I am seeing and hearing when I am totally maxed out does not bother me at all and I am even getting pretty good at picking out the good tones and actually can notice the good numbers on the screen if only for a brief instant.
Of course it would not be a good idea to lock me in a room with anybody and especially with any sharp objects within easy reach, but regarding THIS stuff I am becoming extremely comfortable and calm.

 

[WhatTheBeep]

Oh, I bet tinnitus would be rough with headphones and a detector.

Well, I'm not that much of a metal head... just wanted to see what kind of distances I could get compared to my old F2 with settings cranked up. I can't run those settings in the field much at all. Even when I can crank Sens up to 90 in SL speed without EMI chatter, once the coil starts moving I pick up way too many short signals for me to deal with properly for very long.

Thanks for the tips, too... I can definitely use 'em.

WTB

 

[Steve O]

The sensitivity of these "F" units are undeniable. If you don't know it, they pick up iron rust flakes and scatter gun shot. I dig buck shot more than I care to, especially the copper shot. They like hot rocks with mostly mid tones. The hot rocks set off the Garrett pro pointer also. As far as coils go, it's hard to beat the 11"dd for separation and depth.

 

[dbax]

Steve O, you got that right. I have picked up some really small stuff too, and deep, considering how small. I remember finding my first BB and think this coil would be for gold, if it were just a bit smaller. I have found bits and pieces of jewelry and buttons -- I have to admit, however, without my Garrett pin pointer I would be lost. Even the coins hide really well in the dirt around here. Lucky for me, unlike your, I do not have to contend with "shot", but my areas of hunt it is the bottle cap. Yes, I have read and tried all of the tricks and tips but that signal comes though so strong on certain caps you just gotta dig. Like the old really rusty nail, an old steel bottle cap, rusted down to near nothing will ping like a silver quarter at 8" and who is not going to dig that? In fact, when I dug up those two walking silver half dollars (a couple of weeks apart) they were both at around 7" and both I thought might be bottle cap. Both coins it turns our were up on edge. The newer aluminum caps sing out like dimes in the dirt and on the surface like quarters. Aluminum bits, I think pieces chopped up by the mowers make nice nickel sounds and ping in at 30-31. Ignore them and leave behind nickels. I hope I live long enough to see the first MRI detector -- by then all metal detecting will probably be banned, it will be like hunting, only on private land and only by permission. .