Swing Speed and Overlap

[Dan Hughes]

Everybody tells you you'll find more if you slow down. But slow down what?

Your swing speed? Your walking speed?

This program gives you a step-by-step procedure for determining the proper swing speed for your standard-coil detector, and it also tells you the secret of getting a beep from the deepest coins your detector is capable of finding.

Listen at http://thetreasurecorner.com.

P.S. How many of those coins in the drawing would YOU find?

Dan Hughes, http://treasuremanual.com

 

[Tuberale]

Totally depends on 1) your coil type and 2) how many overlaps per coil diameter you are willing to make. Not all coils are designed like your illustration, Dan. Some have more of a tubular detection range, and can find most 6" or under coins under the coil. In general, especially for cheaper detectors, the diagram is accurate.

Therefore, the question remains: how much overlap are you willing to use when searching? For every 8 inches length searched, do you swing 1x (1 time), 2x, 4x, 6x, 8x? If you make 8 overlaps, you should find all of the coins in your diagram. The diagram also clearly implicates how it is possible to continue finding coins in "worked out" parks for a long time into the future. The key is knowing how your detector and coil works, and to what depth.

I think this thread deserves nominating, too, as it is VERY important, even if many detector users don't understand the principles.

 

[Dan Hughes]

Thanks, Tuberale. When I was describing the signal shape, I said "standard coil," but I should have emphasized that some of the pricier machines use coils with different patterns.

Most of my shows are aimed at relative beginners, and I think the majority of beginners start with an "entry level" machine that has a standard coil. And hopefully, those with a Double-D coil know what they've got!

Although....
__________

 

[Frankn]

Dan, I quiver every time I see that inverted dunce cone pattern! A coil is an antenna that has been bent around in a circle. In fact there are two antennas in there. An antenna radiates out in all directions. You can prove this simple fact by placing a metal object above or beside the coil. This is also the reason all new detectors have non metallic lower rods. The signal radiates out in more or less a big circle. It picks up better on the bottom because the detector is ground balanced. Sure the signal tapers, but it does it way down there. If that cone were true, I wouldn't be picking up large objects at 2' with my 10 year old XLT. Frank

 

[Dan Hughes]

If that cone were true, I wouldn't be picking up large objects at 2' with my 10 year old XLT. Frank

Sure you would, Frank! That cone represents reaction with a coin-sized object, not a garbage can lid. Or are you finding coins at 2'?

I'll admit my radio electronics understanding of it all is a bit fuzzy, even though I have a 1st Class Radiotelephone Operator's License and a ham radio Technician license (and I taught radio broadcasting for 26 years - admittedly, with an emphasis on the art side rather than the technical side, but I did cover the basic electronics stuff).

I think you'll agree that the larger the object, the deeper you can detect it. So that cone diagram is dependent on the target size being a constant.

Help me here; this is what I have been taught:

The basic TR detector is composed of two circular antennas, a send antenna and a receive antenna. The signal is projected downward (and upward, which hopefully doesn't matter) by the transmit antenna, and when it hits metal it "bounces" back,where it is picked up by the receive antenna and then analyzed by the detector's circuitry. The higher the conductivity factor of the metal, the stronger the return signal. And your discrimination control measures the strength of the returning signal, disregarding all signals below your discrimination point.

As for the nonmetallic vs metallic lower rod, it's my understanding that as long as the rod is stationary (immobile in regards to the coil), it will have no adverse affect on the signal, because the receive coil is sensitive only to changes in the signal, and if the metal rod doesn't move there, it causes no signal change.

Some may ask, if that's all there is to it, why don't they make the antennas more powerful so the system can read deeper signals? And the answer is that the more powerful the system, the less stable it becomes. That's why you get so many false signals when you crank up your sensitivity.

Further analysis is welcome! We're all here to learn, including me.

Thanks Frank! Looking forward to hearing back from you.

 

[Tuberale]

I'll happily admit my ignorance here. My degree is in music education. But Gib Thompson at White's did help me through the electronic theory of TR detecting many years ago. And his explanation is basically the same as yours, Dan. In fact, isn't that why the the coil is referred to as a Transmitter-Receiver?

That said, some detectors have more sophisticated detection electronics. I remember hearing about one of the Mighty Mite detectors, that one with a red housing had much greater sensitivity than the green housing. And I knew someone who had one of these relatively early detectors, that regularly ran circles around us other poor slobs. Cheap machine, but great electronics!

I have found that my brain is a better discriminator than most detectors, just because I have perfect pitch. It is not much of a gift, as some musical performances are painful to me. Nonetheless, if I raise the threashhold level ever so slightly, I have gotten faint signals my brain interprets as "goodies" at 8-10 inches locally. Often these are deep silver. Sometimes they are very deep square nails (which I don't mind finding at all, as they indicate I'm doing the right things in the right areas). Sometimes they are hard-to-find IHs.