triple tone on a penny ???

[dfmike]

I went for my first hunt of the season with the CoRe and 5 X 10 open coil in DI3. Conditions were horrendous with almost everything covered in snow. I managed to hunt a few patches that were clear and unfrozen. Got some clad and trash mainly. I got a triple high tone signal which I don't get very often and decided to dig. I got a stinking penny out, replaced the plug and passed the coil over the area again... Nothing. I was stumped. I'm used to getting double tones on pull tabs or ring shaped objects but a triple tone on a penny ??? Anybody experienced a triple tone on a coin before ?

 

[NMchaser]

Yes, I have experienced the triple tone several tines on penny's near the surface. Initially I thought it was several targets close together. It happened again yesterday. I was using the 5 x 10 and DI3 on my Racer 2. None of the penny's were on the surface. Just near the surface. The hole was checked for other targets but none were close by. Also the ground was damp.

 

[Monte]

I used to use the solid-body 5½X10 DD elliptical coil but now only own and use the 5X9½ DD open-frame coil on my CoRe and Relic as a general-use coil for all open areas with a low to moderate trash content. It's a terrific coil but since it is a Double-D design that can sometimes effect the audible search results we get.

Yes, I am no different than anyone else and have experienced a "Triple Tone" audio response from time-to-time. It can happen, but what causes this to occur?

Triple, or even more multiple responses, are caused by one of two reasons:

1.. Logically, there are multiple targets in very close proximity the detector is responding to.

2.. The size or shape of the target causes the multiple response, or a more frequent reason is that the metal object is too close to the search coil and that very close relationship to the EMF and to the Transmit and Receive windings causes the errant response.

So, with a Triple or Multiple Response we are alerted to the fact that one of the Double Causes could be that the target is on the surface or a very shallow, sub-surface object and that the search coil is too close to the target to function properly. That then suggests an odd-shaped, such as an elongated, object, or just possibly that the Single Reminder here is that we are searching with the coil too close to the ground/target. This happens a lot when people unknowingly use a 'scrubbing' technique that we shouldn't be using with our more modern, high-tech detectors.

In the User Manual, Page 6 in the top-right depiction we are reminded to operate with the search coil ±2" off the ground. This is really a recommendation from most detector manufacturers for the past couple of decades, but we do sometimes find ourselves searching with the coil on or too close to the ground and that can cause several issues, one of which is a Triple or Multiple Tone or response.

Keep in mind, too, that due to the irregular shape of the Tx and Rx EMF's of a Double-D coil's overlapping design it tends to pose a greater likelihood of multiple responses on near-proximity targets than a similar-size Concentric coil.

Monte

 

[dfmike]

Thanks for the info Monte. If I recall correctly I used a probe to flip out the penny so it was surely very close to the surface. It could account for the triple tone. I'm just glad it doesn't happen too often.

I do tend to leave just a very small air gap between the coil and the ground.