Higher GB = Less Sens?

vferrari

Silver Member
Jul 19, 2015
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XP Deus with HF/x35 Coils and Mi6 Pinpointer/ML Equinox 600/800/ML Tarsacci MDT 8000 GPX 4800/Garrett ATX/Fisher F75 DST/Tek G2+/Delta/Whites MXT/Nokta Simplex/Garrett Carrot
Primary Interest:
All Treasure Hunting
First of all a high GB number does not necessarily mean high mineralization, but it is a probable indicator. The only way to know for sure that mineralization is driving the GB number high is if you have a mineralization meter on your detector like the Deus, F75, and other detectors. Note also, this is even murkier on the Equinox because each search profile mode will give you a different GB number on the same patch of ground (that is why you need to GB each mode separately at a site). Also, if you are getting a lot of ground feedback noise in all metal (before you ground balance) that manifests itself as wildly bouncing negative VDI's -9 to -7 then that is indicative of the need to GB and also may indicate high mineralization.

Presuming in all likelihood your high GB numbers are indeed due to high mineralization, then as long as you have a sat ground balance you should not have to lower sensitivity at all. If you do periodic checks and find your GB number changing a lot at the site, then don't be afraid to put the detector in to tracking ground balance. Lowering sensitivity is recommended when you still have falsing (with the coil in the air) after a noise cancel (presuming you have eliminated sources of emi for which you have control like cell phones) or if you are hunting in thick iron or trash and you don't overload the detector so you can ferret out keeper mid or high-conductors (this is called "sifting"). Of course, any time you lower sensitivity you will loose depth but that may be the right tradeoff. I would definitely not lower sensitivity solely due to mineralization though. The reason being is that mineralization already limits signal penetration (raw depth) and lowering sensitivity just makes that problem worse. If your detector has the ability to adjust TRANSMIT POWER however (like a Deus) that is what you want to lower when in high mineralization because the higher power transmitted signal tends to get scattered more by mineralization (high beam in fog analogy). The Equinox does not allow manual adjustment of transmit power and only automatically reduces transmit power in beach mode 2 when it senses large amounts of black sand mineralization. You definitely do not want to use beach mode 2 in high mineralization land digging situations, however, because it is optimized for salt ground conditions.

So bottom line, in mineralized soil (presuming not a high junk environment), use whatever search profile you want (other than beach) based on the target of interest, noise cancel, GB (switch to GB tracking), and only lower sensitivity as necessary to get the machine running stable because you want to run with as much sensitivity as you can to counter depth loss due to mineralization. HTH
 

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charlives

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Jan 16, 2012
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Primary Interest:
Relic Hunting
Thanks, vferrari! Nice write-up!
 

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