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Black Sand Query


TripleT

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I have a question regarding how the Equinox throttles back sensitivity when it encounters black sand.

If I am running at 17 sensitivity on a salt water beach and detect over black sand; the machine throttles back sensitivity.   

By how much does it do this? What would be the sensitivity when the black sand indicator is active at 17?

This leads me to wonder. If running at 25 sensitivity and the machine encounters black sand, is it going to be a higher number than the previous scenario?

I also realize, that at 25 the machine will probably throttle back sensitivity much sooner than at 17...

Just curious, thanks!

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43 minutes ago, TripleT said:

I have a question regarding how the Equinox throttles back sensitivity when it encounters black sand.

If I am running at 17 sensitivity on a salt water beach and detect over black sand; the machine throttles back sensitivity.   

By how much does it do this? What would be the sensitivity when the black sand indicator is active at 17?

This leads me to wonder. If running at 25 sensitivity and the machine encounters black sand, is it going to be a higher number than the previous scenario?

I also realize, that at 25 the machine will probably throttle back sensitivity much sooner than at 17...

Just curious, thanks!

What is a black sand indicator???  Do you mean the overload symbol?  Need more of an explanation. 

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Yes, the triangle with exclamation mark in middle.  Overload indicator. 

Sorry, I got use to calling it a black sand indicator,  'cause it only activates for me when on black sand...

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The overload symbol is not about the normal receive sensitivity, which is what the sensitivity control sets. It is about the built in transmit power being reduced to deal with adverse conditions. The Equinox senses when there is too much signal blowback from saltwater or black sand or both. When a detectors "sees" too much salt or too much black sand (or both) it will go totally blind unless the transmit signal is reduced. Going into overload is not reducing depth - it is giving you depth when the machine would otherwise be non-functional.

The overload will not go away until the conditions creating it go away. The only time I have seen the overload signal is when crossing areas on a beach obviously loaded with magnetite. The overload symbol comes on and the detector keeps running fine, then the symbol goes away once past the magnetite patch. I do not know what intensity of mineralization it takes to trigger the process, but it is quite a lot.

Difficult Areas – Black Sand
Some beaches contain black sand, which has high natural iron content and is often magnetic. This causes continuous false ferrous detections, making normal beach detecting impossible. Beach Mode automatically senses black sand and reduces the transmit power to ensure that targets can still be detected without overloading occurring. When black sand is sensed, the Beach Overload Indicator will appear on the LCD. When this icon disappears, full transmit power automatically resumes.

minelab-equinox-beach-2-mode.jpg.ee06e33

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The overload indicator - / work on the reduced Tx .... / on Equinox turns on until the magnetite concentration reaches a certain level - from my observations it is somewhere from the limit of 20-30% of the Magnetite concentration in Black Sand - when using multifrequency..and 11" standart Coil...

The mere reduction of the detector's sensitivity does not affect .. the change of the detector's resistance to such a phenomenon ..

A small 6 "coil will be less resistant to higher levels of Magnetite Concentration in Black Sand than an 11" standard coil.

----------------------------------------------------------------------------------

BlackSand Test boxes with 4.4% .., 12%, .. and 33% Magnetite concentration ..

IMG_20200531_170044.jpg

IMG_20200531_181445.jpg

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Bklein .... you can buy powder magnetite in a store that sells
  chemical materials- iron oxides Fe3o4 / Fe2o3 .. for laboratories, technicians, ..or for schools ...

Iron oxide Fe3o4 / magnetite / can be mixed with construction sand in a weight ratio of 1 kg magnetite to 20 kg fine-grained sand - you get Black sand with a 5% concentration of Magnetite - which represents 7 Bar - the maximum value on the mineralization meter for Fisher f75 / F19 detectors. .or u XP Deus / ORX detector ..

IMG_3050.JPG

 

IMG_3057.JPG

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  • 1 month later...

 

A short test and demonstration of the work of Equinox 800 on super extreme mineralization - with a content of 97% magnetite ...

 

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