dbax said:
Thanks yowow that is just the kind of info I was after. It seems to me that it is the machine that makes the coil, not the coil that makes the machine. The F2 is a good machine and I have found a lot of stuff but nothing like what I am uncovering with the F70, but REVIER found a real use for it, especially with the 4" coil in searching special areas. Guess I was hoping the coil would somehow make this F2 more powerful than it really is. I think it is operating in the 8.5 HZ zone, while the F70 is above 13 HZ in all of its 7 settings -- hey, maybe some kind of buster could be wired into the F2/F4?

No, I am joking -- I think

You are right, common sense tells me this too, good money on top of bad -- new machine would be the better investment. Besides this is a loaner, my wife's machine
Since you mentioned me I will give you my thoughts on this one.
I have read that F2 owners that have this one are split...some love it some not so much.
More seem like it than the amount that are not impressed.
I never got one for my F2 for a few reasons.
One, I already had a large one for my Vaquero so buying one for my F2 seemed a bit redundant, but I loved using that big coil in wide open areas where I wanted to cover a lot of ground.
The wider scanning field is an advantage in that situation because you don't have to overlap so much and I had some pretty good confidence that it was not missing much at those large open sites so the "what ifs" didn't bother me so much.
I very well could have missed some targets but it didn't seem that way in my mind so that worked for me.
I did use that Vaq and coil set up here in Kansas at a park in one of those wide open areas one day and at the end of a hunt with not much to show for the last half hour I was literally running around one of these open areas swinging the coil so fast you would have laughed because I looked like a hockey play moving down the ice on a power play looking for one last "Hail Mary" good target.
As funny as it looked this actually worked and I did get a quick signal, stopped and went back to examine it further and found a 14k nice gold ring on that one.
There is a possibility I might have found it using that detector or others including the F2 and concentric coils, but to this day I am convinced that it was the wide scanning field of that coil along with the fast speed of the Tesoro, which the F2 is close to equal in that area, that actually enabled me to acquire and even notice that signal as fast as I was moving that day.
In the area of mineralization I have always read that the DD coils handle it better and I have read many posts from hunters in areas of mineralized soil that have found this to be true with 1-2" or more in depth achievable over concentrics...including the 10" coil for the F2.
If I did get one for use on my F2 when I lived in Birmingham I really don't believe that would have been the result for me because in that area we not only had super heavy mineralization but also a severe problem with iron and that limited depth on all detectors and coils so virtually every detector was pretty much on an even playing field in the worst of that stuff.
None of us got much depth no matter what we swung and no matter what brand or coil.
I believe only a PI unit would have made any headway in that devil dirt and I seriously considered getting one but then I moved to extremely great soil in Kansas so it became a none issue.
That is actually why I got the 10X12 DD coil for the Vaq by the way, to get better depth, but in my case I don't believe it helped at all and I don't think getting a DD coil for the F2 would have either.
Here in my much better soil concentrics can go pretty deep so before I got my F70 and was still using the F2 the most I did get curious and bough a 10" concentric to see if it actually would go deeper than the 8", even though I still used the sniper coil almost exclusively due to my targeting densely packed trash areas the most.
I have read that the DD's are very good in trash...the longer thinner scanning field can snake through trash pretty well, but I still believe that sniper coils are better for doing this and you can isolate all signals better and get better target info due to the fact there is less possibility of having more than one target under that coil at the same time.
Turns out on the few times I did use it the 10" concentric did go deeper than my 8", I got better clearer signals on targets 5" and more, too, and even though you have to overlap more than when using the DD I think for like
half the money of that DD coil the 10" is a
great value and found me a couple of really great things even though I have limited time using it.
Less area on the scanning field but in good soil the 10" concentric might actually go a bit deeper than the DD coil, I have read, and this might actually be true but I never compared both types of coils on the F2 in any kind of soil so I can't say for sure.
Another plus is that the 10" coil, along with the sniper, for me seemed to have a little less problems and issues with heavy EMI than the 8" coil does.
None are perfectly quiet, especially when you hunt like I do on full sense most of the time, but in my experience the 8" standard coil that is supplied with the F2 is the worst out of all of them when it comes to noise and EMI problems.
Another reason I usually preferred to use concentrics over DD's is that bottle cap problem inherent on most brands using these coils.
DD's are a little less sharp in discrimination so those high tone bottle caps seem to mimic dimes and quarters pretty good, very, very good as a matter of fact in their tones and behavior, or at least they did using my Vaq and a DD coil.
This was a real drag for me when I was in older areas where a ton of these things were everywhere.
Now that I use the F70 and have had some experience using both concentrics and DD coils I have found this is not such a problem when using units with screens.
The bulk of these problem targets do come in at different numbers on the screen than good targets like dimes and quarters so you can usually tell, plus you can use a technique called "rimming" to figure these out better, also.
By running the edge of the coil, including and especially the DD coil, over these caps and not the center of the coil these things seem to drop from high tones and numbers down to the iron levels and low numbers most of the time.
This actually works using the Vaquero too, but you have to manipulate the knob back down to iron to check on these and that takes longer and still a drag for impatient ol' me so using the Vaq and DD coil still not my favorite way to hunt trashy parks with a lot of these things...using the F70 and DD coils seems to be much easier and less fatiguing physically and mentally.
I assume this would probably work using the F2 and a DD coil, but again, I have never had any experience using that set up.
All in all in my experience and considering the way I hunt and the areas that I hunt the 10" concentric made more sense as a coil upgrade on my F2 for more depth and the much lower price over the DD just clinched it.
As in all cases since you don't live where I do, hunt the way I do or maybe not even the same type of sites your mileage may very.
Honestly, I am on a new journey with the F70 now, I have 3 coils and that fine machine to play with and learn, and as much as I love that F2 I don't see myself using it all that much anymore so spending any more money on it, especially over $100 for a DD coil, would again seem redundant and silly.
Since you already have the F70 and the 11" DD coil, and considering with all that extra power a whole different animal compared to the F2 and a DD coil, I would think you would be in a similar position.