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Tejon and Discrimination

Canewrap

New member
I started detecting about 3 years ago with beep-dig machines and one of the things I quickly figured out was there is a loss in detection depth with the use of discrimination. Well, after 3 years of using a number of TID type machines I'm back to using a Tesoro (Tejon to be specific). Does anyone that has extensive experience with the Tejon have any idea of about how much depth is lost when turning up the discrimination with this machine? I know I'm probably going to have to run some tests to figure it out for myself, but I could really use some help here. What I'm looking for are approximates. Like if I set the second disc at foil, about how deep will it see targets in good ground? How about how much difference in depth is there between all metal and just after clicking out of all metal? When after deep targets this is something we need to know.

TIA,
Bill W.
 
Looking for Scully to pipe in ...

I set up the most prevalent soda can pop top type of tab to just click on the second discriminator. I have dug some tabs that were clicking in the 6 to7 inch range and have dug nickles that sounded great at 9 inches when on the first discriminator set at foil and went away completely on the second discriminator that the tabs click on.

I have not pushed the test on how the depth curve changes when you get close to the discriminator, but have been very happy with the depth on nickles in good ground with the discriminators on foil and tab.
Cheers,
tvr
 
I am a relic hunter and almost never hunt with my primary disc above the foil setting. But even at a disc setting on foil, "Iffy" targets come in stronger in all metal. So even slight discrimination will have an effect. Toss in ground cover, moisture (or lack of it), and some mineralization, and you can have a wide variety of results.

I really couldnt tell you how much depth you loose as you turn the disc up, but it should be a relatively simple test to do because the Tejon air-tests so well. Use a nickel, you should get between 12-14 inches with sensitivity at max (about 9.5 or 10), with disc down on the "I" in "FOIL". Slowly crank the disc up and watch your depth decrease. Granted, this is only a relative test because actual soil conditions can change a lot of parameters, but it will give you an idea of how much you could be losing.
 
I've tried these test on buried targets and they're not acurate. The disturbed ground makes it look like a rejected target to the detector. I emailed Tesoro once with this question and was told it would lose about 1 1/2 inches. I usually run the second disc to barely accept a nickel. I've dug bullets in the 10 to 12 inch range with a very faint signal. This was in wet ground.
 
It will vary on the user. If you super tune in all metal, I can see some one easily lose 2 inches by switching to disc mode. Still, the tejon is a pretty deep machine on coins if you are hunting in disc mode. It will also depend on the size of the item. For small 3mm metal shards, the tejon wont even pick them up in disc mode...
 
NVmar said:
If you super tune in all metal, I can see some one easily lose 2 inches by switching to disc mode.

I actually spent a fair amount of time with the Tejon with the head phone volume way up, finding faint targets in all metal. I'd then switch to discriminate with the first discriminator between iron and foil. I was amazed that in discriminate I got very good beeps on everything I heard in all metal.

My soil tends to be pretty mild so it may not be the same where you are; so it is a data point I had in my conditions.
tvr
 
tvr, if signal is louder on disk and hardly diserneble in all metal, then your ground balance is off. all you need to do is slightly turn the knob to the positive side to get a good signal...disc mode, though deep, should never be deeper than all metal.
 
NVmar said:
disc mode, though deep, should never be deeper than all metal

Didn't mean to imply deeper ... but just as deep in both modes in most of my hunting conditions.

Monte taught me that the Tesoro detectors ground balance for deepest detection in discriminate mode when ground balanced a little bit negative of the all metal neutral setting. My testing showed that to be true over my ground.

In my mild ground I have found that my deepest detection in all-metal with the Tejon is with it set to not change threshold when bobbing. In discriminate mode, if ground balance is set so that it nulls slightly on the down stroke of the bobbing with the pinpoint pulled, it will detect and beep fairly well on virtually every thing that it detects in all-metal with a neutral ground balance setting.

I have also found that my CZ's will detect and give reasonable ID (although averaged down on the real deep ones) in discriminate mode on everything that I can find in all-metal.
tvr
 
tvr said:
NVmar said:
disc mode, though deep, should never be deeper than all metal

Didn't mean to imply deeper ... but just as deep in both modes in most of my hunting conditions.

Monte taught me that the Tesoro detectors ground balance for deepest detection in discriminate mode when ground balanced a little bit negative of the all metal neutral setting. My testing showed that to be true over my ground.

In my mild ground I have found that my deepest detection in all-metal with the Tejon is with it set to not change threshold when bobbing. In discriminate mode, if ground balance is set so that it nulls slightly on the down stroke of the bobbing with the pinpoint pulled, it will detect and beep fairly well on virtually every thing that it detects in all-metal with a neutral ground balance setting.

I have also found that my CZ's will detect and give reasonable ID (although averaged down on the real deep ones) in discriminate mode on everything
that I can find in all-metal.
tvr

Don't get me wrong, I agree with you on this matter. On most good size items like coins, disc mode is good enough to detect them at a good depth. I'm referring to the minute items. If you go relic hunting in disc mode you will definitely miss items since the whole purpose of disc mode is to discriminate against certain alloys in the first place.

Like I said in my original post, the tejon won't pick up really small metal shards in disc mode. On the other hand, those same shards will be easily discernible in all-metal...

I rarely hunt in disc mode. Then again, I don't hunt for coins.
 
Agreed.

Mass makes a difference as well as structure. A 3 mm diameter ball bearing is detectable to pretty good depths in discriminate or all-metal. A splatter of lead, 3 mm wide but thin and porous may not beep at all if small nails are discriminated out but can be detected well in all metal.

Sometime I would like to hunt some of the areas known to have gold and learn to deal with the ground types you are normally working with.
Cheers,
tvr
 
tvr said:
Sometime I would like to hunt some of the areas known to have gold and learn to deal with the ground types you are normally working with.
Cheers,
tvr

Oh, it's hard to cope with the ground types where gold usually resides. So much so that many people often leave the hobby.

I have placed hundreds of hours on my machine, and I'm an optimist. I do think you can successfully use the tejon to find gold but the learning curve is very steep. When you're out on mountainsides you can not dig every strong signal. You have to put aside norms about metal detecting . Otherwise, if you do dig every signal, you will have realized the majority of your time digging rocks, which is very frustrating. The awesome thing is that the tejon is a very predictable machine. For instance, if you have a strong signal, common sense will guide you to dig. However, when you're out on the gold fields, you have to go over that same signal 3-4 times and get more information about the signal. If the signal is not pronounced at the same time and place (in other words, if the signal "moves"), then you have to hold back your reflex to dig and resume detecting elsewhere. You have to employ different strategies from coin detecting. I mean who would have ever thought a signal could move!

I have also found strong signals right on the ground surface. When I first started, I remember encountering strong signals only to have them disappear right after digging. I found this very annoying and made me question the tejon's reliability. I would ask myself how could a very strong signal disappear (even if strongly detectable in disk mode!) after digging only a few inches of ground? Then I realized that those grounds have been undisturbed for a long, long time (hundreds, thousands of years probably). Corrosion naturally deposits minerals at certain locations. Then I realized that scraping the ground surface with the side of my shoe would make those signals disappear. Wild! Specially considering that these signals were very loud, dig signals, the types that would blow your head away with their intensity. The tejon was detecting the minerals on coil.

I remember being out in the middle of nowhere one day. I had spend so much time digging lead (you will dig a lot of lead if you're hunting gold. So much so that you will end up regretting the 2nd amendment ), so I followed this one trail on google maps that led me near these mountains very far away. I was still new so I was practically digging everything to get myself familiar with the different signals. Having spend probably 9 hrs that day, it was getting dark. I was tired, running out of water, and my feet were sore. I was getting ready to leave when I got this beep.

As odd as it may sound, when you're out in the field, you're not going to get weak beeps. Bury a dime and detect it at 7 inches in disk mode and you'll have an idea: The beep, though weak has it's traits. Move your coil 90 degrees several times and if the signal does not move you know the object is circular in shape. Raise your coil further out and if the beep is still reproducible, though more faint, you have an idea of its depth. Like a coin signal with it's particular traits, my signal also had its distinct, reproducible traits: it was faint, but a very reproducible sound. Also, what made the signal special was that I was able to reproduce it in disk mode. 9.999 out of 10 times, you're not going to reproduce a weak signal in disk mode and have it remain faint. If you're able to reproduce it, most likely, the signal is going to be very loud. Because the signal was very faint, and it remained faint in disk mode, I knew I had something special. Because it was weak, if the object was small (bb sized) I knew it was at most 3 inches deep. Otherwise, it could be a larger object (half dime sized) and be buried at around 5-7 inches (yes, even with the tejon, 3 inches may not sound deep, but you have to realize that naturally occurring metals are not usually found placer. Most precious metals are found at microscopic levels embedded in rock. The industry extracts several ounces of metals from tons of these lode deposits).

So after noting all of the peculiarities I dig.

I get down to 2.5 inches and find this rock...I was ready to break my tejon in half when I realize that there were no other rocks around, the ground was relatively clean, somewhat compact. So I pick up this fucking rock and look it closer.

To this day I have no idea what the small rock is (4-5mm at most), but it's clearly some kind of metal. It is perforated like the inside of bone, but very light for its size. I want to say it's a meteorite of some kind because it's magnetized (I can lift it with a magnet), but it's light weight confuses me. ...i dunno,all i know is that it's not yellow...

There are a few other techniques you can employ. However, doing so just makes the whole experience frustrating. Specially when you can get your self a decent PI unit and not have to worry about keeping track of what you are not doing or are doing wrong. I don't blame my tejon for the frustrations I have encountered in gold detecting. The best way to describe my experience is like trying to change a watch battery with a mallet and pincers. Though you can change a watch battery with a mallet and pincers, aren't you better off employing more appropriate tools? The tejon was designed to be a relic hunter. It's unmatched at doing what it does best, and relic hunting is what the tejon does best. The tejon wasn't designed for the peculiarities of hunting gold.

I'm not saying that you can't use the machine for hunting gold. All i'm saying is that you have a lot of learning to do in order to get around the limitations of VLF. Still, I love my tejon.
 
You've presented a lot of great thoughts about various techniques. Sizing and locating from multiple directions; different 90 degree sweeps (or as I like to do, circle a target as it also helps unmask from trash), coil height for depth sensing and others!

Thanks for sharing!

A few years back, I picked up a copy of "Follow the Drywashers" by Jim Straight. It has a lot of gold field detecting information, written nearly 20 years ago. A very good read! ... although I still have not made it to likely gold areas with a detector.
Cheers,
tvr
 
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