Has anyone EVER thought of a concentric coil of this shape?

[Sean_Goddard]

I was musing on making a "widescan" concentric coil and scribbled up the attached file. No calculations done propeerly, but you can adjust to suit. I used Dave Emery's formula of turns for the area. Might work. Might not.

[Reg]

Hi Sean,

I couldn't open the file? Any reason for using a zip file?

Reg

[Sean_Goddard]

Hi, The file is an MDI file for Mircosoft Office graphics and it's a FULL size A3 10" plot of the coil.

I only have access to Microsoft Office where I am at the moment as security on the network is VERY tight.

Try it as a .DOC for Word file.

BTW the name of the coil is a trademark of mine. =-)

[Reg]

Sorry Sean,

I still can't open it. I must be doing something wrong.

Hopefully, someone will be able to open it and post it in a different format.

Reg

[Ray-NM]

here it is in jpg format. If I uploaded correctlyu

[Reg]

Hi Guys,

Jeez, thanks for opening the pic Ray. Now, I am not thinking today. Must be because of my 12 hour night shift last night. Anyway, for some strange reason, the jpg format came to me via email. That is good because I couldn't find it at the Geotech forum. Again, must be something I am doing wrong. Maybe when I wake up, it will make sense.

I have uploaded it again so I can see it if I need to again.

Now, as for the design, Fisher built a coil very similar where the transmit was round and the receive was elliptical. A search for Fisher coils will display the coil or skid plate.

I have experimented a little with the design on a PI, but not a VLF. When building it on a PI, I didn't add the canceling windings though. I need to do that. When I built it, I used the Fisher skid plate for the housing. Now,

Reg

[Sean_Goddard]

Thanks for that Ray!

Well, if Fisher built one it MUST work!!

Interesting that they seem to have run out of ideas recently thought. Shame.

[Reg]

Hi Guys,

What would be interesting would be to build a typical concentric coil and then simply test it for depth, etc. Then elongate the center coil something like you have posted and try it again. It would be interesting to see if there was any difference in performance and if so, in what way.

Reg