On Threshold and Sensitivity

SLGuin

US Midwest

Joined Sep 6 2020

Posted on October 14, 2020 @ 8:29 PM

These two seem connected in a way, yet not in a clearly defined way. In fact, what threshold does on a Tarsacci is not clear at all to me. One more way the Tarsacci differs from other detectors. Low sensitivity and threshold settings work better in trash, and unlike some there is not nearly as much loss of depth or small targets as a person might be used to. Here, thresh -9 and sens 3 is often used when the ground is tough. It is surprising how small and deep it goes even at very low settings, and even in presence of trash.

In clean ground, it can of course be turned up, but there does not seem to be the big advantage to running hot to the point of barely stable as there is with some. Anyone got input into why this might be so? Do you run hot or cold and how do you decide what settings to use? 

All of these threads are in aid of finding some metric to determine optimal. Less clear cut sometimes with a Tarsacci, but worth figuring out. It is of course personal preference in a lot of ways, but a rationale would be nice too. For me, the settings are determined by what seems to work best hunting relatively shallow in high junk. It is to limit it in some ways to make sense in an environment where there is too much trash signal that sounds too much like good target, For as long as aluminum looks like gold this will be a running battle, but playing with the concept is a joy.

Dave.H

South West UK

Joined Jul 14 2020

Posted on October 31, 2020 @ 12:48 PM

 

SL,,, you've raised some interesting questions/thoughts about the Threshold & Sensitivity settings!

 

I managed to get out detecting yesterday for a few hours here in the UK,, horrible field, of which "green waste" had been deposited a few years ago, almost making it impossible to search since! ,,, almost completely covered in mostly small shredded pieces of TIN FOIL.

However, a high Salinity Balance, and a relatively low Sensitivity & Threshold setting allowed this site to be searched with some degree of success, so much so , it's made me think that the Tarsacci, especially for inland difficult sites, i.e. iron / contamination/ minerals etc, is much more adapted with the lower settings!,, to be honest when I look back over the last 3 months using the MDT 8000, I've actually found that I've been indeed gradually lowering both the Threshold and Sensitivity settings with NO apparent loss in targets! (Probably a increase)

 

To conclude, For difficult areas,, SENS... 3, 4, max of 5.  THRESHOLD... -9, -8, -7....... STABLE MACHINE,,, HEAR MORE...DEEP TARGETS MAYBE FAINT,,,,, BUT STILL AUDIBLE...

(I ONLY USE MIXED MODE FOR SOUND)

Regards 

Dave.H

 

 

 

 

SLGuin

US Midwest

Joined Sep 6 2020

Posted on November 4, 2020 @ 7:41 AM

Dave,

You are exactly right. High salt balance with low sensitivity and threshold seem best for difficult land sites. The unique properties of the MDT allow hunting the bad ground and trash like no other detector though. It is a joy to use, and the lower settings seem best for land sites pretty much all the time now. Public ground gets pounded hard here so unmasking missed targets is the order of the day every day.

This particular question received no other response, so thanks for chiming in. It is difficult to understand this machine in common terms, it is quite unlike normal VLF, or even a PI which it resembles in operation to some extent. Asking basic questions does not always bring help for that understanding, thankfully the thing is at least easy to use even if it cannot be entirely understood. The easy to use part comes from the folks sharing their knowledge. Thanks to you all for that.

S