Metal Detecting: The Spherical Field & Using The TR Circuit
December 1st 2006 16:45
Metal Detecting: The Spherical Field
Coins on edge are a favorite subject among metal detectorists, and that does provide some good subject matter because many coins actually fall into the ground edge first. It was very difficult to find coins on edge with older detectors, and this was because there was very little coin-surface area exposed to the metal detectors field, by which eddie currents could form and thereby cause the opposition necessary to react with the field. Though it could be done by the adepts, and in clean, worked out, but real good areas, this detection mode has been actively sought by some psychos, to squeeze that last coin of super age and make out of the ground. Gold coins are sometimes deep.
With the advent of the phase analyzation circuit in metal detectors came not only good metal discriminating capabilities but also a more distinct and electronically observable spherical electronic field. A 3D effect. This is how I see it anyway. The simultaneous measurement of the phase which is 180 degrees off the primary signal allowed a greater detection capability for coins on edge. Be aware of those musical flutters! The on-edge coins are certainly at all sites, and this is very fun to think about and do.
Metal Detecting w/ The Transmitter Receiver Circuit
The Transmitter Receiver Mode of a metal detector is a discriminating mode that does NOT require movement for a signal to happen, and it also discerns between ferrous and non-ferrous pretty well. TR mode is a good tool when hunting an area loaded with bottlecaps, to see what is there and if it is worth cleaning the area for the other targets. The problem with the TR circuitry is it lacks depth, and can be erratic under certain circumstances. Knowing this, you can employ it when possible, and it lends that much more flexibility to your efforts.
The TR circuit on Whites Coinmasters is tuned by holding the coil up about waist height and getting a minimal tone from the tuner while holding the reset button/toggle in. Then release the toggle and begin lowering the coil to the ground. As the coil is lowered to the ground, it will invariably go into null sound, no sound. The sooner this happens as the coil is lowered, the more effect the ground is having on the circuit. At about 2-6" above the area of your normal swing, reset the tuners tone with the toggle by clicking or depressing it once, then lower the coil all the way to normal swing height.
This is like tuning it to that particular area of ground, and it will null again as it is lowered the last few inches, and you can work in null easily and to good effect. This can be tested by carrying a nickel around with you and checking the situation at the coil as often as necessary by throwing the nickel down and retrieving it. Once you successfully attain null AND good metal detecting results from your tests with the nickel, and if the discriminate button is set at nails or above, then you can pretty much dig every target because only surface iron and good round non-ferrous targets will set the detector off, for the most part. The trick when operating like this is to go slowly and thoroughly.
There are other tuning and use methods for TR circuitry, especially when working around water, so remember experimentation is your friend. More about that in future entries.
Coins on edge are a favorite subject among metal detectorists, and that does provide some good subject matter because many coins actually fall into the ground edge first. It was very difficult to find coins on edge with older detectors, and this was because there was very little coin-surface area exposed to the metal detectors field, by which eddie currents could form and thereby cause the opposition necessary to react with the field. Though it could be done by the adepts, and in clean, worked out, but real good areas, this detection mode has been actively sought by some psychos, to squeeze that last coin of super age and make out of the ground. Gold coins are sometimes deep.
With the advent of the phase analyzation circuit in metal detectors came not only good metal discriminating capabilities but also a more distinct and electronically observable spherical electronic field. A 3D effect. This is how I see it anyway. The simultaneous measurement of the phase which is 180 degrees off the primary signal allowed a greater detection capability for coins on edge. Be aware of those musical flutters! The on-edge coins are certainly at all sites, and this is very fun to think about and do.
Metal Detecting w/ The Transmitter Receiver Circuit
The Transmitter Receiver Mode of a metal detector is a discriminating mode that does NOT require movement for a signal to happen, and it also discerns between ferrous and non-ferrous pretty well. TR mode is a good tool when hunting an area loaded with bottlecaps, to see what is there and if it is worth cleaning the area for the other targets. The problem with the TR circuitry is it lacks depth, and can be erratic under certain circumstances. Knowing this, you can employ it when possible, and it lends that much more flexibility to your efforts.
The TR circuit on Whites Coinmasters is tuned by holding the coil up about waist height and getting a minimal tone from the tuner while holding the reset button/toggle in. Then release the toggle and begin lowering the coil to the ground. As the coil is lowered to the ground, it will invariably go into null sound, no sound. The sooner this happens as the coil is lowered, the more effect the ground is having on the circuit. At about 2-6" above the area of your normal swing, reset the tuners tone with the toggle by clicking or depressing it once, then lower the coil all the way to normal swing height.
This is like tuning it to that particular area of ground, and it will null again as it is lowered the last few inches, and you can work in null easily and to good effect. This can be tested by carrying a nickel around with you and checking the situation at the coil as often as necessary by throwing the nickel down and retrieving it. Once you successfully attain null AND good metal detecting results from your tests with the nickel, and if the discriminate button is set at nails or above, then you can pretty much dig every target because only surface iron and good round non-ferrous targets will set the detector off, for the most part. The trick when operating like this is to go slowly and thoroughly.
There are other tuning and use methods for TR circuitry, especially when working around water, so remember experimentation is your friend. More about that in future entries.
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