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Re: It looks like what?

October 29, 2022 01:54PM
A mono coil pattern is similar to a concentric. Detection patterns depend on the size of the target relative to the coil, my illustration was likely an 8-10" concentric coil and a quarter. A tiny target (say, a 1-grain nugget) might only be detectable right at the perimeter of the RX coil whereas a beer can might be detectable a foot off the edge of the TX coil.

You can calculate the field of any coil using the Biot-Savart law. However, it's only reasonably simple to calculate the field strength along the center axis of a round coil where the r-vector is a constant. Going off-axis results in a solution that involves elliptic integrals and is better suited for computer analysis using finite element modeling. The same is true for elliptical coils, even for the center axis. But, yes, the solution for an AC field is identical to that of a DC field.

If you were to calculate the TX field strength at a bunch of positions in 3D space you could plot the isomagnetic lines which gives the illusion of a detection depth pattern. But it's only the TX half of the round-trip equation and also doesn't account for target size. The only practical way to determine the detection pattern is experimentally.
Subject Author Views Posted

When is it beneficial to Overlap Coil Sweeps?

UtahRich 330 October 20, 2022 11:38AM

How do you walk in a straight line?

GB_Amateur 201 October 22, 2022 10:15AM

GB_Amateur, your addition to this topic fits well.

Monte 186 October 22, 2022 02:18PM

Thanks, Monte

GB_Amateur 232 October 23, 2022 09:57AM

Great questions, Rich. thinkingconfused smiley

Monte 508 October 21, 2022 01:33PM

Re: When is it less productive to overlap coin sweeps?

Sodbuster 186 October 21, 2022 09:36AM

Re: When is it beneficial to Overlap Coil Sweeps?

jmaryt 464 October 20, 2022 06:10PM

j.t., just a brief comment about a 'detection field'.

Monte 170 October 21, 2022 12:21PM

Re: j.t., just a brief comment about a 'detection field'.

jmaryt 204 October 21, 2022 07:02PM

j.t., I agree about the 50% overlap coverage.

Monte 177 October 22, 2022 04:45AM

Re: j.t., I agree about the 50% overlap coverage.

jmaryt 182 October 22, 2022 07:54PM

hmmm . . . . .

UtahRich 194 October 21, 2022 08:41PM

Re: hmmm . . . . .

jmaryt 199 October 22, 2022 08:01PM

It looks like what?

UtahRich 228 October 22, 2022 09:46PM

Re: It looks like what?

Geotech 205 October 27, 2022 12:00PM

Re: It looks like what?

GB_Amateur 176 October 28, 2022 09:52AM

Re: It looks like what?

Geotech 168 October 29, 2022 01:54PM

Re: It looks like what?

GB_Amateur 189 October 30, 2022 09:38AM

Experimenting with your own equipment

UtahRich 192 October 28, 2022 10:42AM

Re: Experimenting with your own equipment

nwdetectorist 170 October 31, 2022 08:49PM

Rich, there is another way to deal with cell phone EMI.

Monte 208 October 29, 2022 10:43AM

Re: Rich, there is another way to deal with cell phone EMI.

jmaryt 164 October 29, 2022 07:20PM

Re: Experimenting with your own equipment

GB_Amateur 175 October 29, 2022 09:46AM

Re: Experimenting with your own equipment

Monte 188 October 29, 2022 10:52AM

Great response.

UtahRich 202 October 27, 2022 04:12PM

Re: It looks like what?

FeistyFrank 185 October 27, 2022 02:44PM

Re: It looks like what?

Geotech 186 October 28, 2022 10:15AM

Thank You, Carl.. Appreciated by many. N/T

Monte 145 October 29, 2022 10:54AM

Re: It looks like what?

FeistyFrank 169 October 28, 2022 11:10AM

Re: It looks like what?

jmaryt 172 October 23, 2022 07:52PM

Descriptions can be confusing. confused smiley

Monte 182 October 24, 2022 12:57PM

Re: Descriptions can be confusing. confused smiley

jmaryt 186 October 24, 2022 06:03PM

j.t., as UtahRich said ... No worries.

Monte 227 October 25, 2022 05:21AM

Re: j.t., as UtahRich said ... No worries.

jmaryt 272 October 25, 2022 05:07PM

Re: Descriptions can be confusing. confused smiley

UtahRich 188 October 24, 2022 07:54PM

Re: Descriptions can be confusing. confused smiley

jmaryt 193 October 25, 2022 05:13PM

Sunrise . . . . sunset . . . .

UtahRich 185 October 26, 2022 01:12AM

Re: Sunrise . . . . sunset . . . .

jmaryt 169 October 26, 2022 06:20PM

Or is that Snow Fal .... Snow Melt ....

Monte 167 October 26, 2022 01:29PM

A better description?

UtahRich 189 October 23, 2022 09:05PM

Rich, I am looking for Carl's post. N/T

Monte 194 October 23, 2022 07:09PM

Yes, the topic can create some interesting discussions.

Monte 189 October 22, 2022 02:35PM



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