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GB_Amateur

3"x6" DD Vs. 5" Round DD For Vlf?

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I have the Fisher F75 black which comes with both the standard 7in X 11in DD and the 5 inch round DD.  They also make a 3 in X 6 in DD (among others).  I like coils but don't like wasting $.  My question is simply:  "Is it likely I'll be able to see much difference (in the positive direction, that is!) if I buy the 3x6?"  I have read a couple posts on another forum reviewing the F75 3x6 coil positively, but I don't know if those people actually had the 5 inch for comparison.

BTW, I'd be happy to hear responses from those who have used 3x6 coils, whether or not they've used the Fisher.  For example, the White's MXT has both a 3x6 and a 5.3 (the latter a concentric, though).

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One of my favourite coils that is within the sizes that you have mantioned and i really enjoy using is the NEL Snake 6.5''x3.5'' i use one on my T2 and also a the UK version of the Vaquero called the Laser Trident11 Extreme,on both of these machines they perform superbly.

 

They cover slightly more ground that the 5'' T2 coil but target separation in my mind is slightly better,on trashy sites then the T2 with the Snake coil is my weapon of choice,then my 2nd choice for the next size up is the NEL SharpShooter 9.5''x5.5'',the Sharpshooter coil on my original green T2 has taken more gold coins ie full and quarter staters than all my other machine put together.

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The Fisher F75  3x6" is an elliptical concentric, not a DD.    I don't use the small coils very often.   For small target hunting I would be more likely to use my 3x6 over my 5" DD just because it IS a concentric. 

But again I don't use them often enough to give you hard information. 

HH
Mike

 

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Hi i am using a 3x6 on my F75 dst and i love it found lots of good stuff with it on the Thames river not cheap as it comes at 105 pounds with a stem but in FA mode 65 sens and 80 GB i am having fun it pays for the machine in 3 outings after 65 sens in IRON infested site i dig more for rubbish and ID is crap 65 is the best for me ......but i guess on cleaner spot you can push it a bit .IT is perfect to search between rocks,founds a 15th century chess rooks,a 11 grams gold 18ct gold fragment a 14ct gold ring with a big diamond and many more stuff...lots of gold with it ...............so i am keeping that one

 

 

RR

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As Mike noted the Fisher 3x6 is a concentric, but there is the NEL Snake DD so you have both options. Are you using the 5" round coil a lot? There is not much difference between various small coils and since you already have the 5" that would be my go-to coil. Unless you are just looking for something to buy :smile:

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4 hours ago, Steve Herschbach said:

Are you using the 5" round coil a lot?

Yes, in the heavy iron infestations.  If the iron isn't so bad I use the 5x10 concentric.  I use the 7x11 the least, but it's a good coil and the deepest.  Given its size and my style of hunting, I need to be in pretty quiet ground (meaning few nails) to be able to take advantage of the depth.  Thus it stays in the cabinet most of the time.  Now I say that probably having run all these coils at too high of a gain for the sites I'm hunting.  But from what I've read and experienced, the more iron, the smaller the coil that works best.

I'm getting a lot of good responses.  I think I'll sit tight with what I've got for a while.  I have a couple other detecting purchases on my list so I'll move those up and a tiny F75 coil down for now.  Thanks to everyone for your info and advice, but don't let me silence anyone.  I'm still listening....

 

 

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my two cents

I borrowed a 6x3 elliptical twice from a hunting buddy for extended periods of time.  I did not have the ability to check targets between the two coils.

In areas with higher grass or stubble, the lack of weight of the 6x3 but having a longer area to have to push through the stubble made it harder to have smooth sweeps for me.

When I would run the F75 in 1n process, the sweet spot of a consistent high enough number to give the monotone seemed to be narrower (front to back) with the elliptical.  I have been doing quite well in finding liberty and shield nickels this year, by focusing on numbers between the 15 and 25 range in the carpets of iron trash, once I get a consistent monotone.  Using the 5", my sweeps can be a bit off the dead center, and still give the monotone, whereas the front or back section of the 6x3 was more likely to not give the consistent tone and then numerical readings to make me dig.  Two sites in particular I hit pretty well with the 6x3 a year ago, and I have pulled 3 liberty nickels from one site and 1shield, a liberty and a couple buffalos as well, using the 5".  

Now that I am using AM almost exclusively when not in extreme trash, I might ask to borrow the coil again, but I have since purchased the 10x5 elliptical, and that in AM does a wonderful job for me.

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57 minutes ago, rod-pa said:

...I have since purchased the 10x5 elliptical, and that in AM does a wonderful job for me.

Thanks for the detailed reply.  Here by "10x5 elliptical" do you mean the open concentric or the closed DD?

 

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Don't know about the F75 but on the Makro Gold Racer and Nokta Gold Finder comparing 5" to the 7.5x4", the elliptical has a sharper response, a clear depth improvement (although small), but bangs a bit harder on hot rocks. 

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    • By GB_Amateur
      Both the F75 and T2 have suped up 'black' versions which have processes called 'boost' and 'cache' that their basic versions don't have.  Sometimes they used 'limited' and 'special edition' to distinguish these, but I don't think those always go hand-in-hand.  Nominally the basic F75 has a gold colored upper shaft while the T2's equivalent is green.  But has that always been the case?  I.e. if a unit has a black shaft (and of course if someone hasn't simply swapped it in for a colored one), does that unit have boost+cache processes?
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    • By Steve Herschbach
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    • By Steve Herschbach
      Snow on the ground so time for a little bench testing. Fisher F75 SE version 7.0A (2013) with 5" round DD coil, Nokta FORS Gold with 5" semi-round DD coil, and White's V3i with 4" x 6" DD coil.



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      The VDI range on the Nokta runs from 1 - 99 with 40 and under generally ferrous. The F75 runs from 1 - 99 with 15 and under generally ferrous. The White's V3i runs from -95 to +95 with negative numbers generally ferrous. I say generally because in all three cases gold can run well into the ferrous range. Like by 10 - 20 VDI numbers into it!

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      Contrast this to the F75 1 - 99 range. There are only 15 points in the ferrous range with the extreme low end represented on the Nokta scale truncated roughly in the middle. However, this leaves 16 up to 62 at zinc penny for a low conductor spread of 46 or slightly better than that on the Nokta FORS and leaves room for a little better definition for high conductive coins also. There is a ten point VDI spread between a dime and a quarter versus only 3 points on the Nokta.

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      The White's V3i slays both of them with White's standard spread of 190 VDI points with half that devoted to ground and ferrous. A full 95 points is devoted to non-ferrous, giving a nice spread across the whole range. The V3i is a three frequency unit and the 22.5 kHz frequency employed allows it to easily nail the ballpoint test with a solid VDI of 3. White's even allows the 22.5 kHz frequency to use a native VDI range that skews and expands the low conductive range that delivers a VDI of 10 on the ballpoint, a very nice cushion between it and a ferrous reading. you have from 1 all the way up to 55 for zinc penny slightly beating both the Nokta and F75 for VDI resolution on low conductors and still room left for very good definition in the high conductor range.

      These detectors can employ a dual tone mode that delivers a low tone on ferrous targets and a higher tone on non-ferrous targets. The break point on the Nokta and F75 is preset at the factory VDI breaks of 13 and 40. The V3i you can customize not only the VDI break point but the tones.

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      Still, tests like these are very valuable to me in setting the baseline for performance in the field from which I can work to discover how much things vary and hopefully why. The theoretical goal if finding a machine that adheres as closely to bench testing results as possible in the field. Sometimes you get textbook results, but then at another location everything goes haywire. But unless you know where you are starting from you will have no idea what is going on.

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    • By Steve Herschbach
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      Now if Fisher would just drop the price of the Fisher F19. I like that machine but at $699 the price is nuts now compared to the other models.
    • By HardPack
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      After reading several of Steve's articles on the Fisher Series and Xterra, here is what I think I have learned:
      The F19 at 19 kHz and Xterra 705 are very close except the Xterra multi-frequency coils selection ( 3, 7.5 & 18.75 kHz); the only waterproof Xterra coils is the 6"; all Fisher coils are waterproof. Not sure if the F19 displays discrim target id in true all metal mode; the Xterra 705 does not. The F19 is a little pricey compared to the Xterra 705. 
      The F75 at 15 KHz 13 kHz in true all metal mode will indicate discrim target id. The Xterra 705 does not display target Id in the prospecting true all metal mode; requires you to toggle over to Coin/Relic Discrim mode for target id resulting in a loss of detecting depth. The F75 Discrim notching is limited compared to the Xterra 705. The F75 apparently has a history of EMI problems; the Xterra does not. The Xterra with a 18.75 KHZ coil runs a little hot for coins and relics but works. The F75 apparent ability to separate out good targets in trashy areas may be a big plus over the Xterra. The F75 stock coil ( 8x11?) may work in the brush. The current base F75 and Xterra 705 price are the same; the F75 Limited Editions $ 250 plus higher.
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      Good prospecting & detecting
      To all you devil dogs out there, have a Merry Christmas where ever you may be. Semper Fi
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