Triple field

[IMF2020]

I have a tech question about a triple field coil .. Is it possible for say a 5" , 10" , 20" ..3 field coil ?? PI or VLF whatever possible ..To me owning many detectors and many coils is stupid and a waste of money ..

 

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[SD51]

Might get a bit too heavy, but not a bad idea...

 

[IMF2020]

The little i know about coils am guessing it would weigh the same as a 20" coil because it uses the same amount of wire if the coils are in series . This would be only be good on land with a harness ..Is vlf possible

 

[Carl-NC]

With PI it is fairly easy and has been done. White's had a dual-field coil for the TDI. A 3-field coil is no harder. However, when sharing the TX & RX amongst multiple coils you will not get the raw depth of a dedicated 20" coil nor the sensitivity of a dedicated 5" coil. You will get a compromise instead.

On VLF a multi-field coil is far more difficult because all coils have to be simultaneously induction-balanced (PI does not). If you could make one, it would be a similar compromise.

 

[IMF2020]

Thanks Carl now i understand

 

[TheGreenBoy]

I used to use 50cm coil with another 15cm coil in the middle - a "dual field" or better a changed magnetic field picture coil on my PI. As Carl mentioned coil is a physical device and instead of two fields you will get a single resultante field. It also manifested a slitely different collapsing curve so the discriminator did not work. Or i was not able to make it work. Overall i did not find it very efficial, assesing the size and depth of the target was nearly impossible, the "target separation" (something PIs doesn't have) was equal to 50cm coil, or none at all in the other words. So yes, it is benificial to use different coils, for better depth, sensitivity or target separation.

The algorythms for excluding small items did not work as well.

 

[IMF2020]

After watching many videos on whites dual field beach machine and comparing it to the sand shark and the ATX am guessing to me it looks to have a small advantage but like u both say its only a compromise . So on land machines i guess it will always be just change the coil size . And in the underwater models fix coil which my dad says all u need is max 6" enless u have millions of $ of gear and a boat bigger then they used in jaws . Thanks again and good luck