Detech 15" Ultimate For Simplex

[Chase Goldman]

29 minutes ago, michaelgolden said:

I couldn't agree with Steve more! For $254.95, The Simplex is the best deal around. There is nothing that can touch it. I get really good depth with it. slightly better then any of my fishers, but the difference is minor, Where the Simplex lacks and this is with the 11' coil is in discrimination in trashy areas. Like all the round 11' in coils I have used, (That goes for the large round Nox coils too.) when I work trashy areas they miss stuff that my Fisher F19 finds with its 10x9 in. Football coil.  One of my tests for new detectors after a break in period  is to use them to search a small area like a section of curb in a big city like Minneapolis or Duluth with lots of trash pull tabs iron etc... Then go over the area afterwards with Fisher F19 to see what the new detector missed.  In every case the fisher found stuff the new detectors missed. The simplex with those 15'/13' huge coils would surely be depth monster, but I really wonder about discrimination issues.. . Never the less it is nice to see Non-OEM coils for the simplex. To bad they are not available for the Noxs.

Best, Michael

Are you actually referring to target separation (ability to discern adjacent targets) vs. target discrimination (ability to identify targets of different material properties (traditionally ferrous from non-ferrous but can also apply to non-ferrous junk (e.g., aluminum vs. gold))?  Larger coils will naturally cover more targets in high density target situations which limits their ability to separate adjacent targets but should generally not affect discrimination ability other than the possibility of ferrous down-averaging of adjacent non-ferrous targets (that is more a function of recovery speed, frequency, and the target signal processing ability of the detector).  So yes, you are abosolutely correct that this coil would likely not be suitable in its ability to separate targets in the situations you describe so your detecting scenarios would not be enhanced with this larger coil.  

p.s. off topic - regarding your statement about non-OEM coils not being available for the Nox, not accurate - Coiltek makes 3 accessory coils for the Equinox -  a 5x10,  a 9x14, and a 15" round.  My apologies if you were strictly referring to the Detech ultimate coil, but that is not how your statement was phrased.

[GB_Amateur]

18 hours ago, Chase Goldman said:

Larger coils will naturally cover more targets in high density target situations which limits their ability to separate adjacent targets but should generally not affect discrimination ability other than the possibility of ferrous down-averaging of adjacent non-ferrous targets (that is more a function of recovery speed, frequency, and the target signal processing ability of the detector).

Let's limit my hypothetical to single frequency operation.  Suppose you have a *lone* target in the ground and further assume that both a medium sized coil (10-11" diameter DD) as well as a large diameter coil (15" diameter DD) both pick it up easily in an air test at a distance X that pushes the limit of the medium coil's ability to give a good dTID.  Now bury the target in mineralized ground at the maximum depth such that the medium sized coil not only detects it but also gives a decent/proper dTID.  Is it a given that the larger coil will also exhibit the proper dTID for this target at that depth, assuming there are no other targets in its field-of-view?

I ask this because the large coil 'sees' more mineralized ground than the medium sized coil.  (I probably should specify a Fe3O4 value for the mineralization, so let's say 4 out of 5 on a Fisher F75.  Thus strongly mineralized but not to an extreme.)

[palzynski]

On 11/13/2021 at 8:18 PM, GB_Amateur said:

....

Detech 13" Ultimate for Fisher F75 -- 532 g

Detech 13" Ultimate for Fisher Gold Bug family -- 549 g

....

Are you sure about these Ultimate 13" weight figures ?  I have just weighted a 13" ( incl the CC ) that I used with a Detech Chaser a few years ago and the result is 591g ... Looks like 530g is rather for a coil without CC ... Unless Detech have changed their coil design
??

[GB_Amateur]

3 hours ago, palzynski said:

Are you sure about these Ultimate 13" weight figures ?  I have just weighted a 13" ( incl the CC ) that I used with a Detech Chaser a few years ago and the result is 591g ... Looks like 530g is rather for a coil without CC ... Unless Detech have changed their coil design
??

The number of windings varies by detector model.  The inductance (and maybe capacitance as well) of the coil needs to match the required inductance of the contol unit circuitry.  That is one reason you typically can't put a coil from detector A on detector B and expect optimal performance.

Both my weight and Simon's did include the coil cover.

[Chase Goldman]

12 hours ago, GB_Amateur said:

Let's limit my hypothetical to single frequency operation.  Suppose you have a *lone* target in the ground and further assume that both a medium sized coil (10-11" diameter DD) as well as a large diameter coil (15" diameter DD) both pick it up easily in an air test at a distance X that pushes the limit of the medium coil's ability to give a good dTID.  Now bury the target in mineralized ground at the maximum depth such that the medium sized coil not only detects it but also gives a decent/proper dTID.  Is it a given that the larger coil will also exhibit the proper dTID for this target at that depth, assuming there are no other targets in its field-of-view?

I ask this because the large coil 'sees' more mineralized ground than the medium sized coil.  (I probably should specify a Fe2O3 value for the mineralization, so let's say 4 out of 5 on a Fisher F75.  Thus strongly mineralized but not to an extreme.)

Good question, Chuck.  I would have to do a test to find out for sure, but I suspect the ground response in highly mineralized soil would favor the medium coil giving a more accurate TID at depth.  With the exception of PI detectors where larger coils do provide a distinct depth advantage, I generally stick with the VLF stock (for Equinox that would be 11”) or smaller coils when detecting in hot ground because anecdotally I have found that ground effects appear to counter any depth or even coverage advantage of the larger coils.  But I have not done controlled testing to verify my theory.

[Pombo2000]

Very good price for black Friday 

 

https://www.thrace-detectors.com/detech-ultimate-13-simplex