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Depth Discrimination
Posted by: Bob38
Date: February 05, 2019 02:50PM
I'm just going to put this out there and see what happens. With today's technology, it would seem that a manufacturer would find a way to add depth discrimination option kind of like the way notch disc works on several units. I often hunt locations where I want to ignore the first 3 inches or so due to the modern clutter. Or at least have the ability to turn the volume down on targets from any depth range. For me, it would help in the discrimination of shallow aluminum when looking for deep silver. Also, the fresh drops in an area you have hunted before such as an annual fair or gathering place.

Tell me what you think but be gentle I have a soft shell and worship the ground each and every person on this forum.

Re: Depth Discrimination
Posted by: dfmike
Date: February 05, 2019 03:51PM
I often wondered about that myself. There is a place I hunt often where there is lots of shallow modern trash and all the old silver coins and relics I have found there have been a good 2-3 inches deeper. I don't think a depth discrimination would be very accurate because of target size and many other variables but I would certainly like to play with it in certain areas. That being said, it doesn't take very long just to push the pin point button to get a good idea of the target depth.

Active detectors and accessories: Fisher F19 LTD on Mars universal shaft, F19 on original shaft, Nokta Fors CoRe, Whites MX7, Makro and Nokta pointers. Killer B's and Jolly Rogers headphones and assorted coils.
Previous detectors in order of acquisition: Bounty Hunter Discovery, Fisher F44, Fisher F5, Omega 8000 V6, Minelab X-Terra 705

Re: Depth Discrimination
Posted by: dan h
Date: February 05, 2019 04:15PM
Surface blanking. Not many detectors have it.

Re: Depth Discrimination
Posted by: still looking 52
Date: February 05, 2019 06:40PM
My F5 has modulated sound which is sort of what your talking about and now after having used the machine awhile I can pretty much tell the difference between swallow and deep targets.
I love hunting for that deep silver and now I can pretty much tell the depth by the sound without using the depth menu option.
Another little trick I've learned is when you get a target just pull the coil off the ground until the sound disappears and look at the distance the coil is off the ground, the further the coil is off the ground the swallower the target.

"surface blanking" was a dismal failure. Here's why :
Posted by: Tom_in_CA
Date: February 05, 2019 07:53PM
There was an attempt, on at least one machine that I recall, back in the late 1980s or early 1990s, that had an option of "surface blanking". Designed for the intention that some types of hunting (typically turf), has newer targets @ shallow, and older targets @ deeper . Conditions where coins tend to be stratified commensurate by age. And a lot of hunters would simply mentally pass shallow signals, in their quest for older deeper whispers in turf. Hence: Why not make the detector have this an automated feature , right ? It's merely a matter of having an intensity meter, where those louder signals are simply filtered into a reject category, eh ? Genius idea, right ? :drool: Designed by George Payne.

But it was unpopular, d/t the "devils in the details". Here's why :

Assume for the moment that there's a shallow memorial penny or soda can or whatever. Naturally, it's a loud signal, right ? But here's the problem: As you're swinging along, and your coil catches the edge/fringe of such a target, it would give a whisper signal. So the user would think "aha !". Yet, of course, when you go criss-cross it (and now you're over the loud center), then PRESTO, it disappears. So you move on to the next target. Only to have the same phenomenon keep repeating over and over. And people found themselves trying to "pinpoint" the flutters of the sides of targets, blah blah blah. It simply didn't work as intended, in actual field conditions.

There was also VERY Poor (almost deceptive) advertising that accompanies that (Marketing dept. genius) : When you saw the magazine ads for this machine, it gave the impression that you were "seeing through" that top 3 or 4" . Ie.: defeating masking. As if that top 3 or 4" magically wasn't there. This was not true at all. You simply nulled out over the larger object AND anything that was underneath it, at the same time.

Thus it's better to let your ears do the work. If you get a machine with full tones and sounds, you will, like still-looking-52 said, be able to use the modulation to tell deep vs shallow. Pretty soon, you'll do it without even thinking.

The exception would be monotone machines. Ie.: the beep-or-no-beep type machines, with no in-between states. Like: machines with audio-depth boosters (where they try to make the "weak signals louder. While that seems like a noble idea (so you're less inclined to miss a deep whisper) yet : You can kiss goodbye any ability to tell deep vs shallow. Best just to train your mind and ears.

Edited 1 time(s). Last edit at 02/05/2019 07:55PM by Tom_in_CA.

Re: Depth Discrimination
Posted by: Bob38
Date: February 05, 2019 08:33PM
Ok I see. Thanks for the explanation. I can see where that would be more trouble than it’s worth.
Thanks again Tom

Re: Depth Discrimination
Posted by: Tom_in_CA
Date: February 05, 2019 09:14PM
.... Ok I see. Thanks for the explanation. ....

You'll get my bill in the mail :blowup:

Re: Depth Discrimination
Posted by: Bob38
Date: February 05, 2019 09:16PM
Just charge it to my account:lmfao:

Re: Depth Discrimination
Posted by: #1Leatherneck
Date: February 07, 2019 08:31AM
White's Spectra V3i will already do much! I have been studying the V3i and there are configurability for mostly what this thread is about.


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