I know some people want to claim that their machine is somehow the deepest or best, I’m not that person. What I will show you is how you how to set your Tejon up to hit 15” quarters and 12” dimes. This demonstration is done with in ground clad coins from my test garden. The 4 and 6 inch coins have been in the ground for 3 1/2 years, the 10 and 12 inch coins have been in the ground less than a month. The soil is a moist, but not muddy, clay loam soil with low mineralization, typical Northern Ohio lawn soil. The machine as tested is a Tesoro Tejon with a Tesoro 12x10 wide scan coil with the scuff cover installed. This machine was bought new 4 years ago, has never been sent back to the factory, and I don’t consider it to be one of the especially hot units.
The first test will be with the following settings: Battery life greater than 3 beeps, sensitivity 10, threshold low hum, ground balance neutral, disc 1 set at foil, disc 2 (trigger forward) set above tab to act as a coin check. The first targets are 3 nickels 4 inches flat, 4 inches on edge, and 6 inches flat, coins are 2 feet apart. Solid hit for all 3 coins, you will find these coins every time on a blind search, trigger forward to disc 2 machine is silent (normal response). Next 3 quarters at the same positions and depths. Again solid response for all 3 coins, trigger forward and still a solid response. Next 3 dimes, solid response on the 4 inch flat and 4 inch on edge, noticeably weaker response on the 6 inch flat dime. You would probably not miss this coin, in fact, it is the sound most of us are especially looking for, but it is near the max depth that you would find this coin outside of a test garden. I don’t have any coins buried at 8 inches, so on to a 10 inch quarter. Very slight response to the 10 inch quarter, I would probably miss this coin in an open field. 12 inch quarter a few peeps, this coin would not be found in this search mode. 10 and 12 inch dimes are silent.
Let’s super tune the machine by increasing the sensitivity to max, the machine is now chattering, reduce sensitivity just until it stops chattering. On my machine that puts the sensitivity knob deep into the red line. Check the 10 and 12 inch targets again, there is a slight improvement in response but none of these coins realistically would be found in an open field. Leaving the sensitivity up, now increase the threshold to max. No change in the response. Next return the threshold to a low hum and turn the ground balance ¼ turn negative, no improvement in response. Ground balance ½ turn negative produces a different sound but offers no real increase in response. Leaving the ground balance ½ turn negative and increasing threshold to max offers no improvement. I also saw no real increase in depth using Monte’s power balance instructions.
Now we are going to try these settings: Sensitivity 10, threshold low hum, ground balance neutral, disc 2 (trigger forward) set all the way counter clockwise to all metal. This is still a motion discrimination mode, the machine will pick up iron, but it will tell me that it is iron. Disc 1 set counter clockwise past the click to slow retune threshold based all metal. Trigger back into pinpoint mode to quickly quiet the machine. Now reduce the threshold just to the point the machine becomes silent but no further. This goes against the book, but you will enjoy hunting this way. Now as you sweep the coil over empty ground you will hear the threshold tone appear and disappear, gently bump the ground balance knob positive or negative to keep the machine silent as you are searching, you no longer have to stop and balance the machine, you can now do it on the fly.
Now try the 10 inch quarter, a good solid response, I would find this coin every time in an open field. Trigger forward, you know the target is there and you now know where it is, use disc 2 to identify it. It has been my experience that Tesoro loses some of its ability to discriminate below 10 inches, pull tabs may sound like coins at this depth, but the machine still is able to deliver a different sound on iron, although, your experience may be different than mine. 12 inch quarter solid response, trigger forward and ID the target. 10 inch dime solid response, trigger forward, only a slight few pips, no useable discriminate info. This target is beyond the range of the discriminator. 12 inch dime solid response, trigger forward, no response and is beyond the range of the discriminator. If I passed the coil over any of these coins in an open field they would be coming home with me. The huge difference in response between threshold based all metal and trigger forward discriminate mode is a good indicator of target depth. At any time you can quickly retune the machine to quiet the threshold by pulling back on the trigger momentarily.
The Tejon still has one more trick up its sleeve. With the machine set to all metal as described above, set the tone control to VCO. The 10 inch quarter produces a response of greater than half the scale. The 12 inch quarter just under half the scale, lift the coil you can still get a solid response for this coin with the coil 3 inches off the ground, that’s a true 15 inch depth on a quarter. 10 inch dime about one third of the scale, 12 inch dime still comes in with a solid sound at about one fourth of the VCO scale.
That’s how you hit a 15 inch quarter and a 12 inch dime. Those numbers are conservative, when I buried these coins the 12 inches was measured with a tape measure from the coin to the top of the ground. Add the height of the grass and the coins are actually about an inch deeper than claimed.
would love to still have one of those machines....
