F75 Confidence meter

[Mike Hillis]

This was being discussed on another forum and I want to copy my post here as well.


Regards the F75...In a nutshell, the confidence meter and the depth meter should not give conflicting reports. When they do give conflicting reports you know that something is amiss.

For example:

If you see a target give a medium or shallow depth reading, yet the confidence meter is low (1 or 2 bars), you know you have a deep, larger than a coin, target. Most of the time you will see this type of response on deep, smashed aluminum cans. You'll get a nice zinc target id in the low 70s, good audio, medium to shallow pinpoint (4" or so) but the confidence meter will show 1 bar.

Whenever the two graphs agree you can have strong confidence in the display output no matter what the number of bars being displayed. When the two graphs disagree, you then have to intrepret the results, keeping in mind that calibration is to US coin size targets.

Hope that helps.
HH
Mike

 

[sprchng]

My 75 ltd hasn't given me an accurate pinpoint depth on a coin since I've had it---what does that say about the "confidence" meter?

 

[tab-nabit]

I've never paid attention to the confidence meter. Maybe I don't have confidence in it. The audio is my determining factor. The VDI & depth I'll look most time for gee-whizz.
Now this will make me look at the confidence meter next F-75 outing just to see

 

[IBdiggin]

Right on Mike. I hunt with an F70 and an elliptical 10" coil. Confidence meter is very handy on the jumpy numbers. This coil is like hunting with an upside down traffic cone so I will pinpoint every suspicious target right away. I feel I need to have the target in the coils sweet spot for the most accurate confidence meter, VDI, and depth evaluations. I use confidence meter not only on oversized trash like cans, slaw, and iron rust deposits but also handy on those really corroded zincolns that like to flicker all the way up to clad dimes if you examine them long enough. Some times helps with nickels hiding in the tabs. I have a lot to learn about confidence meter yet so I appreciate your input here. Now if I could only get a clue what the heck the dirt meter is flickering about at different times----------------Thanks again--IB

HH

 

[dbax]

sprchng, sorry to hear your F75 does not give accurate, or at least, consistent depth readings. I think you should contact Fisher and have a talk with one of their techs. I have the F70 11" DD and the depth meter is spot on. There is a little trick, however, On deep, larger targets, like beer cans, or a pipe or even buried fencing you will sometimes get a solid hit, like a dime at 3", if there is not dime at 3" then you know it is deep trash or a jar lid full attached to a jar full of gold coins -- your choice to dig. These big objects always seem to read in the 3" depth range. On the coins the depth on my F70 is very reliable. The confidence Meter will read the deep object as a dime so if it is not at 3" you have junk (depending on where you live ) if it says it is a Quarter it is most likely a quarter or an old rusty bottle cap. I use the confidence meter all the time and once you give the machine time to lock on it will tell you what it is. These machines have very fast response times but sometimes you need to hover over and iffy target for a bit to get that confidence meter on your side. I use the sound until I stop to read what the sound is telling me, get over the target, do the little wiggle, center, Id and dig or not. Peace Dan -- Love this forum

 

[osgood]

i like tab nab it, dont do much with the confidence meter. All i know if when a descent (like a silver quarter,half dollar etc) is present, the whole machine lights up with those consistent low 90s lock ons, etc. I know it seems odd but usually even all the numbers on the screen, the fonts, if you will, even seem a darker black, (like text that is set on bold). Big deep things that I usually skip, i usually define by estimating the objects size with the swing, left , right, etc. I also do that raising the coil up and up thing-, if its still ringing a foot or two above the ground its either gigantic or very shallow but large. Love the 75ltd! Good Hunts All, CO

 

[rubydot]

I love the confidence meter. As you stated it is very useful to help identify those larger buried targets.

 

[Ayeti65]

I will take all the extra information I can get from my F70, I have noticed that when you get an iffy signal your confidence meter will reflect it also. When digging a good item the confidence meter seems to reflect that also, of course it's not fool proof, but definitely handy, very handy. I try to use it along with the ID numbers and watch to see if they lock in or bounce around some, and as long as the target isn't on edge or a crazy shaped ring that reflects the signal funny the F70 I have will lock down the numbers and show high confidence.

 

[markg]

You are exactly right Mike. But sadly saying a lot of users ignore that function.

 

[Rusty Nails]

I love the confidence meter. As you stated it is very useful to help identify those larger buried targets.

I agree, I pay more attention to tones and that than I do the VDI numbers.

 

[Dave J.]

"Confidence meter" works differently in different models. They all work, but differently. The factory does not disclose the underlying algorithms.

 

[ez4sure]

I think the confidence meter in mild soil is much more accurate in soil like we have on the west coast targets past the 4 to 5 inch range and the confidence meter is not reliable.

 

[pasttom]

"Confidence meter" works differently in different models. They all work, but differently. The factory does not disclose the underlying algorithms.

Just as well. What would it help and who would actually understand it anyway? End users are like the audience at a magic show. Magicians are NEVER supposed to reveal how it is done. If it works we are delighted and that is what matters.
I know there are some who just have to push the envelope and see behind the curtain (and that is okay), but for the 99% rest of us... Wow, thanks Dave and crew!

 

[markg]

Always look forward to Dave J. jumping in, he brings a lot of insights to the subjects.

 

[WhatTheBeep]

Always look forward to Dave J. jumping in, he brings a lot of insights to the subjects.

Totally agree!