Menu
What's new
Find's Treasure Forums

Welcome to Find's Treasure Forums, Guests!

You are viewing this forums as a guest which limits you to read only status.

Only registered members may post stories, questions, classifieds, reply to other posts, contact other members using built in messaging and use many other features found on these forums.

Why not register and join us today? It's free! (We don't share your email addresses with anyone.) We keep email addresses of our users to protect them and others from bad people posting things they shouldn't.

Click here to register!

Need Support Help?

Cannot log in?, click here to have new password emailed to you

Changed email? Forgot to update your account with new email address? Need assistance with something else?, click here to go to Find's Support Form and fill out the form.

Ace 250 target ID and notching??

A

Anonymous

Guest
Am I reading the posts right here? A while back it was noted that the modern square tabs people wiggle and break off pop cans read right at nickel and now I just read a post down below where alum screwcaps if notched out take zincs with them. Don't sound good to me!! I realze no detector is perfect but with all the notch zones available on the 250 along with the frequency it operates at IMO, it should do better than this.
Where do rusty bottlecaps come in??
Tom
 
I just looked at a pic of the control panel and the way the notches and ID segments are set up. 12 segments and most are wasted on high coins leaving little resolution on the trash type targets.
Tom
 
if the bad target exactly mimicks a good target. My minelab Explorer will give two readings for each target, sometimes the readings are IDENTICAL for a nickel and a square tab.
Sometimes nickels vary by one digit, 10-05/10-06 sometimes the pulltab varies 10-04/10-05/10-06/11-05/11-06/11-07. Sometimes they look exactly like a nickel, sometimes only VERY slightly different. With 31*31 possible discrimination "notches" the Explorer offers a theoretical 961 notches. In real world conditions (soil/tab depth/tab orientation/etc...) it would be ill advised to notch out square pulltabs and hope to dig only nickels.
Look at how many people display "this weeks finds" with ANY machine. Lots of quarters, lots of pennies (zinc or bronze), lots of dimes, lots of other goodies, but almost never are their lots of nickels. The ones that show a nice cache of nickels are the ones that dig lots of tabs, or are blessed with litter free sites where IDENTICAL interference singals do not exist.
As for rusty bottle caps, that's even more fun since the act of the rust diffusing through the ground makes for an ever changing target. One year a particular cap might look like an easily rejected piece of iron, the next year it might show up like a "clean" quarter to MOST machines.
The goal then is to reduce the trash signals to a manageable level, but when the signals you are searching for happen to be identical to the signals you wish to ignore, your only chi=oice is to approach the target from many angles and try and decipher it's true comosition by the subtlties your detector provides.
In summary, square pulltabs are hard to discriminate on a machine offering 961 discrimination points, it will by definition be harder to discriminate them on a machine barely breaking double digits.
Does that mean the Ace isn't up to the task? Not in my mind, since in order to make it up the the task, it must offer nearly 1000 "notches", and even THEN will still not prevent you from digging junk tabs!!
Let's not forget that gold looks like "junk" too, so we just have to grin and bear it sometimes. If we're smart, we collect those tabs we dig, they represent the effort we put in, give us practice amking clean holes to refill nicely, and most important, get them out of the ground so next time we sweep that area all we get are good signals.
Have a great day, and don't let the tabs bust your chops!
DAS
 
First off, you have to count the 0 reading on the Explorers as a target can read 0, 31 or 31,0 so there are actually 32 x 32 possibilities for the ferrous and conductivity readings on an Explorer which leads to 1024 possible target IDs - note that this makes sense in a modern computrized machine as 1024 is a power of 2 and computers use power of 2 arithmetic (or binary).
Anyway, I think JadkPine's point is still valid that if all pulltabs and all nickels fall in the same notch then it limits the usefulness of that notch. You yourself noted that there are several possible readings for pulltabs on the Explorer and you can get to know the signature that the common pulltabs in a particular spot can make. For example I hunt at a beach during most of the winter and the snack bar at that beach only sells soda that uses one type of pulltab. I know the reading (and sound) that particular type of pulltab makes and it is different from nickels most of the time.
However you main point about the differing circumstances such as the amount of corrosion, orientation and other factors can cause a target such as a nickel to read differently than one normally does.
I would throw gold rings in there too as I am much more excited when I dig a pultab like target and come up with a gold ring than if it is a nickel. If you have pulltabs notched out then you are going to miss at least some of the rings. Still 12 notches means comprimising some on the utility of the notches as they have to block out such large chunks of the spectrum. Geez I wish my GTI1500 had more than 24 possible target ID/notches though it doesn't need as many as my Explorer has. Seems like 64 or perhaps 96 would be a good number of them.
 
These nickels were mixed with dimes in the same hole. I got a reading around the quarter to half range and was surprised with 11 coins. Pull tabs are a pain but its like Varmint said. So dig em and learn. I dig the lead sinkers too. You never know.
 
zero as a number (being a design engineer), but I think we can agree that zero in this case means zero discrimination, thus my conscious descision to reduce the number of DISCRIMINATION points to 961!
All in good fun though, but if I had said 1024, somebody would have corrected that too!!
And I did briefly mention gold (though not specifically in ring form). <img src="/metal/html/smile.gif" border=0 width=15 height=15 alt=":)">
DAS</STRONG>
 
that the best our nation can offer these days are coins that decay into nothingness in a very few short years?
Seriously, it BOTHERS me to dig a zinc penny and find it with holes clean through, entire edges missing, etc...
Talk about a "throw away society"!
In the future they'll decide the "once great Americans quit producing coinage sometime around the year xxxx".
Have a great day, and happy hunting.
DAS
 
take my time, or use a spell-checker!
Arghhh!
(Thanks though)!
DAS
 
Varmint,
True words,
I had an Explorer too,(Great machine,)lots of accept/reject points...
I thought it was THE answer to discrimination woes,
with it's seemingly endless disc. possibilities;
BUT...
I found, (as you say,) there are many things out there with the same electronic footprint...
Someone said on one of the forums that the best discriminator is a shovel !!!
And you really don't know what you've got 'til you dig it do you !
SNOWY
 
Varmint,
You make very good points and I agree. The problem is most people in the market segment the Ace is aimed toward don't have the experience we have and need all the help they can get. In my experience a large percentage of alum screwcaps hit in a range that is well between zinc and copper/dimes and a properly designed segment in that range should not take out zincs, nothing is perfect as it would eliminate some of the older wheats.
At around 7 Khz the response on high conductive items is well spread out, so IMO there is no excuse for this. Instead Garrett chose to show icons/segments for each coin denomination. My point is that 12 segments properly setup could do better for the casual coinshooting most will use the 250 for!
Tom
 
Steve,
I hunted some modern parks and campgrounds last fall with one of the newer mid priced ID machines and it did a great job of ID'ing the new square tabs while still letting me dig nickels. It was better and easier to use than its high priced sibling for modern sites!
Tom
 
Ah but its not descrimination it is the inductance or conductivity value of the target in question. So a target can have a conductivity reading from 0 to 31 and an inductance reading from 0 to 31, so there are 32 possible values for both conductivity and inductance thus 32x32, not 31x31.
 
Get into edit mode and select the smallest cursor. Using the vertical axis control buttons, move the cursor as high as it will go. That is position 1. Count the number of presses of the down button it takes to reach the bottom of the screen.
Don't let the cursor movement fool you, the bounding box has 45 pixels (not counting the single pixel border) in the vertical axis. The software will move the cursor 1 pixel sometimes, and 2 pixels at other times in order to cover the screen in, you guessed it, 31 steps.
Of course the effect is greatly exagerated in the horizontal axis, moving 2 or 3 pixels per navigation button press, but in this case, the sofware WILL allow 32 points to be independently selected.
So, I therefore modify my asertion of 961 possible points of discrimination to 992.
(First time I checked the steps I got 31 on the horizontal axis as well as the vertical, but when I rechecked for this post it did indicate 32).
Again, most post was based on the number of discrimination points possible (selectable), not the number of points the machine itself can resolve.
No matter which numbers you settle on, happy hunting. The principals behind my post are 100% intact, that being even 992 (now) points of discrimination are inadequate to completely eliminate falsing "trash" items for "good".
DAS
 
I did the test as you suggested and got 32 press both ways to move the cursor from top to bottom and from side to side.
I thought I recalled reading something about this in Andy Sabisch's book "Mastering the Minelab Explorer" so I got out my copy and found a reference in the book indicating that there are 32 vertical and 32 horizontal steps. It is on pages 65 thru 69 in the chapter entitled, "Understanding the Display".
 
I get 31 vertical and 32 horizontal. I must have a noisy pushbutton that double hits exactly once in 30 presses!
So be it, the post still stands, you can never discriminate all garbage and never miss goodies.
What I find interesting is how freakishly often pull tabs or especially the break away disc from a supposedly "captive" can design looks like a nickel to various machines. Down to one part in 992 in fact.
Tried it another 20 times, I still get 31 in the vertical, every single time.
DAS
</STRONG>
 
You must log in or register to reply here.
Top