F-75 VDI readings (Updated 5/25)

[Charlie P. (NY)]

I have an ongoing project and here are some baby photos of what I hope will be a useful pursuit. I am logging every find in a notebook and tracking them on the following three graphs.

The first is the bars as displayed on the F-75. The second is the same but with the ranges in groups of three (have you noticed the numbers are not evenly progressive on the display template?) The third is true VDI readings along the full scale.

These are with my unit, in my soil, as I observe them. Your findings may vary. You'll note in the first one for every treasure there is trash in the same range. Luckily the "good stuff" sounds smoother in audio and stays steadier on the display.

(Updated 5/25 for colors and added coins)

 

[Mark in NC]

if you and Mike Hillis (graphed out the Coinstrike) ever team up, no target will be safe!

 

[Bill Ladd]

n/t

 

[Charlie P. (NY)]

Enlightened self interest. My Musketeer has three knobs and none of them are calibrated in any way. There is kind of a jazz/zen thing about the settings and it's all by "feel". Suddenly, I have a way to measure, quantify and test for repeatability. I have to re-learn detecting. Though the audio of the F-75 is familiar ground. There are mode/tone combinations that are similar to the vocabulary of the Musky. I'm still hearing things that are new on the F-75. Ran it over a piece of brass screening just under the grass and it sounded like a 70's fire truck when they first switched to electric sirens. The overload noise on the Musky sounded like an Fox Terrier on a rat. "GRRRRRRRRRRRRRR!" I would actually laugh to hear it.

Something about the F-75 bottle cap mode gives that same "smuck" noise at the beginning or end of squashed trash. When I hear that I know it's junk . . . I think. Now I have to resign myself to the hard work of digging EVERYTHING until I know the language. I've been having fun up to now coin-shooting.

 

[Anonymous]

n/t

 

[jeff@middlesex]

n/t

 

[BobH]

n/t

 

[jim tn]

That is good stuff and reinforces many of our readings. (Except, for me, the gold coins, for one item) HH jim tn

 

[Charlie P. (NY)]

Oh yes. In fact, at our club's Spring fun hunt I let one of our members try out the detector and he dug a steel bottle cap. I just didn't write the number down. As I say, this is a work in progress and will be added to as items surface.

 

[Idaho-Marke]

n/t

 

[BobH]

...although it's almost a tossup.

 

[Charlie P. (NY)]

Not really. I was inconsistant between the two charts . . . maybe I'll fix that. Black was trash. I wanted to show the discrimination and notch; it's blue in one and red in another. In the long chart the sliver is light gray, copper brown, gold yellow. In the other "good" is gold and "bad" is black.

I gotta tell you right out that the gold is speculation based on an old edition of Charles Garrett's Modern Metal Detectors. The next gold coin I dig will be my first.

Update 5/25 - I went back through and made the colors consistant through all three charts. The red is my "coin-shooting" discrimination and notch settings and should be approached with caution as it may cost you items you'd rather not miss. Works well in my usual town park that's full of food & drink related trash.

 

[Jeb NWR]

Although i`m from the UK. i`m impressed with the dedication this guy shows to go to such lengths, for the benefit of others. Well done .

 

[Charlie P. (NY)]

Must be genetic. Grandpa was a Pearsall and Grandma was a Bentley.

 

[Charlie P. (NY)]

[quote BobH]No steel bottle caps in your neck of the woods?[/quote]

I just went out and pulled the notch off at the park and set my discrimination way down (taking a big chance - last time I did this I ended up getting married). Put it on jewelry mode with the sensitivity at 31. 45 minutes of hunting.

Really rusty bottle cap with one edge crushed in - 80 to 93 in one direction, 56 to 70 in the other. No wonder I haven't dug one. Audio was clicky and chirpy.

Also: two quarters, one dime and seven cents (and a pulltab that read 45 that I dug because it was "45" in all directions. And a 3" piece of rusty wire with a nice loop on one end - like the pin of a fire-extinguisher. LOTS more signals but nothing tempting.