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F75 no threshold in disc
Posted by: Ronk
Date: November 30, 2017 07:42PM
Since the threshold on the F75 doesn't carry over to disc then what would be the setting if it was compared to below zero or above zero like all metal or neither? Sorry I'm not too technical minded. Is it preset?

Re: F75 no threshold in disc
Posted by: WV62
Date: November 30, 2017 09:17PM
That would be question for the mother ship (First Texas).

I disc the F75 is setup from the factory for silent search.

As a user I have learned to just except the fact that there is no threshold sound.

Ron in WV

Worked and lived in the Huntington West Virginia area all my life, retired 2010
US Air Force Vietnam Veteran (68-69 & 70-71)
Started getting into metal detecting around 1975

Yes it is silent search-
Posted by: vlad
Date: November 30, 2017 10:48PM
I would suspect D Johnson has it as close to the barest audio as possible.I prefer a threshold because it gives me an idea of the ground changing, along with nulls
letting me know I'm walking over targets discriminated out.
You could try running it a little high in sensitivity to get some noise which in a way is a threshold. Or put it in stat mode with a variable threshold---that kind of power you have never seen.
But the numbers do jump more--its literally something you have to learn-stat if used correctly will properly identify round iron better than any motion mode (7/11DD.)

Re: F75 no threshold in disc
Posted by: Ronk
Date: December 01, 2017 12:44AM
I wasn't referring to actually hearing the threshold in disc mode. I was only curious of how close to the null point it is set whether it's slightly below or above. I realize we have to accept the fact that it's silent search in the disc which is fine for me. I Do search in all metal when conditions allow and experiment with different threshold settings.

Re: F75 no threshold in disc
Posted by: mheastboston1
Date: December 01, 2017 03:42AM
Sounds like your talking about audio plus or minus??

Re: F75 no threshold in disc
Posted by: REVIER
Date: December 01, 2017 05:09AM
The F70/Patriot is built on the same platform and startup thresh settings on those are -3 so to assume the F75's in disc would be about the same probably wouldn't be a stretch.

Neither has DST and when they added that into the F75 I believe they raised the gain from startup 60 to 80 so there is a possibility the thresh got bumped a bit too but I assume it is still below 0...but don't quote me because I really don't have a clue.
Could be the thresh is now at 0 or higher for all I know.
Maybe Dave J. Will pop in here and tell us sometime soon.

"What if doing the Hokey Pokey really IS what it's all about?”
F70, F2, Compadre, Mojave, Judge2 - 2018....Mostly just some clad so far...more to come!

Edited 1 time(s). Last edit at 12/01/2017 05:20AM by REVIER.

Re: F75 no threshold in disc
Posted by: Mike Hillis
Date: December 01, 2017 11:12AM
Hi Ronk,
The Sensitivity setting controls the threshold settings of the F75 in Disc mode. Remember, the F75 only has two (2) gain settings. Low and High. Sensitivity setting of 1-29 control the threshold in the Low Gain setting and Sensitivity settings of 30 - 99 control the threshold settings in the High gain setting.

Disc mode employs additional filtering that requires a set signal strength to work, so the Disc threshold and AM threshold are not really apples to apples comparisons.

I guess you could compare where the Visual Id kicks in at the different settings of Disc and AM and make a comparison of that.

The F70's Threshold control in Disc is there primarily for noise control. Think of it as a pre-DST EMI control. The default setting was chosen for EMI stability reasons.


*****Fisher F75 LTD w/DST ***** Whites V3 ***** Teknetics G2+LTD *****Minelab E-Trac*****Teknetics ETPro *****Teknetics Omega 8500***** Tesoro Golden Sabre II *****Tesoro Compadre *****Rutus Alter71*****

Edited 2 time(s). Last edit at 12/01/2017 11:17AM by Mike Hillis.

Re: F75 no threshold in disc
Posted by: Ronk
Date: December 01, 2017 07:23PM
Thanks for all comments! I think I'm starting to understand about the Threshold finally.

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