Depth expectations? Fisher f4

0z0ne

Senior Member
Joined
Aug 16, 2011
Messages
389
Location
Boulder
Howdy my good people!

Got my f4 a few days back and already put between 20-30 hours on it!
It's been good to me so far, and I love it, but I've a question for those of you who know from personal experience or elsewhere.

How much depth am I to expect with the 11dd coil in DECENTLY good soil?
Northburban chicago has pretty good soil to work with but I seem to be averaging about 4 inches. Perhaps it's the soil, perhaps not. Maybe all the coins around here are four inches or less under the surface, but I doubt it.

I run it in DiSC mode with the sensitivity around 75-100% depending on where I'm at. I would say 85% is average.

I know coins sink, I know there is silver where I'm hunting. I just hope I'll be able to ping down far enough to read it!
 
I have an F2 and found a lot of silver coins with it. My method is to discrim out ONLY Iron and run the high sensitivity. I notice a lot of my deeper finds with machine prouduced really bouncy TID numbers and tones ranging from Nickle to Quarter and Beyond. (34-88) for deeper silver dimes. The machine really locks onto shallow coins, but the deep stuff will be found with tones and numbers varying by a great degree at times. It should easily go down 8inches, but the proper ID of the target won't be as obvious.
 
Hey Jressman!

Thanks for the great input! I'll keep that in mind for sure.

From Boston, eh? I'm from andover! Moved away about a year ago :p
 
I would agree that 8" is accurate. I've found larger relics at 14" as well.

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One of these days, my F4 is going to find a deep cache. :) Really great machine and that DD coil is awesome.
 
The depth will be about the same... Learn about coils here:

http://www.garrett.com/hobbysite/pdfs/searchcoil_tech_sheet.pdf

The Double-D configuration is designed to significantly reduce ground interference and, thereby, recover the performance lost by a concentric coil over mineralized soil. With the Double-D, it is the arrangement of the TX and RX coils that produce a canceling effect of ground signals.

This configuration is called DD because both TX and RX coils are in the shape of a "D". The positive detection field of the DD runs beneath the overlapping center section from front-to-back. The remaining portion of the coil actually produces negative (i.e. canceling) detection fields. It is this canceling field that allows the DD coil to maintain performance over mineralized ground.

Because of its small positive detection field, the DD is inherently less sensitive than a concentric searchcoil of the same size, over non-mineralized ground. The Double-D will, however, significantly outperform the concentric coil over mineralized ground. For this reason, it is highly recommended when hunting over mineralized ground commonly found when prospecting and relic hunting.
 
I'm running the 11" DD coil on my F2 and love it! I like how targets seem to register a lot stabler on the VDI too. I hunt in non-mineralized soil for the most part.
 
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