2-5 meters depth on a cola can

[green]

Have seen the statement posted in some threads. Been wondering what I would need to get my PI detector to detect a cola can at 2 meters. I can detect a cola can about 3/4 meters, 20cm coil with 1A peak Tx current. To detect at 2 meters I would need to increase S/N 360 times, to detect 5 meters increase S/N 88000 times. Some questions. Does 3/4 meters with 20cm coil at 1A peak current seem reasonable or should it be a lot greater distance? Does the math make sense? What can I try to increase signal other than increasing coil diameter, coil inductance and peak current?

[rickb]

Do sane people actually dig that deep on the hope that something of value will be found? Mechanical digger or shovel?

[Koala]

I've dug a few cans out at nearly a meter with an IDX and a 10" coil.

No fun and a waste of time. Doesn't take too many to ruin a days detecting. 8" coil is much better. You loose no depth on small targets but doesn't pick up those deep cans.


Why anyone would choose to detect beyond a meter makes no sense to me here in the UK. Unless you like collecting bits of farm machinery.

[Koala]

increase coil size. 20 cm less than 8". Try 15" coil if you want to search for cans ?

just tried a F1265X with an 8" coil and a vimto can. Maxes out at 60 cm and nice tone to 55 cm

[green]

increase coil size. 20 cm less than 8". Try 15" coil if you want to search for cans ?

just tried a F1265X with an 8" coil and a vimto can. Maxes out at 60 cm and nice tone to 55 cm

Not wanting to search for cans. Would need a ladder to get out of a 2meter deep hole, a TALL ladder with a 5meter deep hole. 2 to 5meter depth for a cola can, 24inch quarter and a 14inch dime are some examples of detection depth that the detector I've been building won't detect. Just wondering what I would need to do so it would. Coil diameter, inductance and peak current effect Rx target signal, anything else? Coil diameter and inductance can effect noise level. Amplifier noise and integrator can effect noise level. S/N controls detection depth. With zero noise, 5meter depth for a cola can should be possible. Wondering if noise level or target Rx signal is the reason my detector won't detect the above examples. Maybe something else I'm missing? (distance vs amplitude_17 chart) I can detect a cola can about 3/4 meters, 20cm coil with 1A peak Tx current. If S/N was increased 3 times, the 1meter coil could detect the can at 2meters. Would increase the detection depth for the quarter and the dime also. Don't like the idea of swinging a 1meter coil. How to improve S/N in the detector circuit? (distance vs amplitude_1)signal level was adjusted for 100 at 6usec(start of 10usec sample). If end of sample was 100, average would be 100. analog integrator gain=Rfdbk/Rin*sample time*sample rate. Assumes signal at start and end of sample is the same. For a 1usec TC target, output would .1 times start amplitude(integrator gain=1). How much would digital sampling and averaging improve detection depth for short TC targets, longer TC targets? Keep thinking I'm missing something else, maybe important.

[Melbeta]

Guys, one meter is around 3 foot deep. Two meters is 6 feet, 5 meters is 15 feet. I was a metal detector dealer in the past, and I knew of NO machine that would detect a small can such as a cola can that deep. Only the LORD GOD can find a cola can that deep. Now you can fool with the detector, and fool with the coil, and you might achieve the depth of 3 foot deep. But not 6 foot to 15 feet deep.......
Melbeta