questions about depth readings

[cybourgh]

Unlike some on this forum I don't have the energy to dig everything so I try to dig only the deep good sounding signals. I have notice that when the depth indicator on the 3030 reads 4" or less the coins are clad dimes/quarters or memorial pennies. However, even some 5-6" readings are really only 3 or 4" down and they also turn out to be clad/zincolns. So has anyone found that the depth reading is not very reliable? Are there settings or methods to improve the depth accuracy? How does a detector measure depth?

 

[C&RHunter]

I have found that on most coin size targets, that the depth indication seems to be very close with the CTX, when you have an accurate pinpointed location of the target.. However, if you don't get an accurate pinpoint on the target, the indicated depth is not as accurate. This may not be exactly correct, but if the target is several inches to the side of the coil center, the depth indication is probably the diagonal distance from the coil center to the target. A coin on edge at 3", may show deeper than it is, due to the difficulty to pinpoint and get the center of the coil exactly over the target. I have seen this to be the case with any of my machines.

I don't know "how" a depth is obtained, but must be something to do with comparison of signal strength of outgoing signal to returning signal and estimated target size?

 

[wildherre]

I have found that on most coin size targets, that the depth indication seems to be very close with the CTX, when you have an accurate pinpointed location of the target.. However, if you don't get an accurate pinpoint on the target, the indicated depth is not as accurate. This may not be exactly correct, but if the target is several inches to the side of the coil center, the depth indication is probably the diagonal distance from the coil center to the target. A coin on edge at 3", may show deeper than it is, due to the difficulty to pinpoint and get the center of the coil exactly over the target. I have seen this to be the case with any of my machines.

I don't know "how" a depth is obtained, but must be something to do with comparison of signal strength of outgoing signal to returning signal and estimated target size?

The only thing I would add to that is that the rapid deterioration of the zinc pennies does affect ID and depth readings but have found most other coins depth estimates to be pretty accurate if properly centered when taking the reading... wildherre

 

[jimzilla]

CR hunter is right on. If you're not right over the target then you will get an inaccurate reading. Also coins on edge tend to be shallower than indicated

 

[Dr.Deus]

I also noticed this.. If you center the coil directly over the target you will get its near accurate depths reading. but if you find the target in the center of the coil, as youre swinging with short sweeps (inch or so) move the coil back a little from center you will notice the depths numbers increasing as you move away from the center. The same results if you move the coil up away from the target while sweeping.

 

[Cowboy26a]

The Etrac was the same way. The closer the target got to the center of the coil, the shallower the depth reading got.