Cylinder Coils?

[Altra]

Nice chart Carl. How did you measure R(100kHz)?

[Carl-NC]

Here are my results, measured from coils I built:



All coils are d_eff = 10" (25cm) and 40 turns which gives ~1mH for a scramble-wound coil. B₀ is the field strength at the center of the coil, B₁₀ is the field strength 10" away. The solenoidal coil (what I assume you are asking about) has the 2nd worst field strength performance, but the lowest parasitic capacitance. This only looks at the TX side but the RX side will be similar. I was actually a bit surprised by how poorly the solenoidal coil performed, I assumed it would be about as good and possibly better than a scramble-wound coil. But apparently the physical height of the coil reduces the effectiveness of the "highest" windings. I think I ran this in FEMM and saw the same thing.

[Detectorist#1]

Flat coil in vertical position will have more more height in comparison with standard mono coil

[Detectorist#1]

Attached is picture with 3 variants of a mono coil. Double height haves only cylindrical coil in comparison with standard mono. For which option you thing?

[Nova]

G'day Detectorist#1, i am not 100% certain, he or someone else did show a picture of a small coil (this coil looked like a typical mono but was double the height) so i am assuming the winding is flat wound but on a vertical plane instead of horizontally, can you picture that?

[Detectorist#1]

What you mean by "cylinder coil" - single row long coil?

[Nova]

G'day everyone, i'm just after some knowledge regarding Cylinder coils, on a detecting forum there was a fellow i believe he goes by the name "Chet" and he has experimented a little with building his own coils, he mentioned that the Cylinder style coil has the greatest depth out of any design, (that is i believe a vertical flatwound coil which will make the housing much thicker), if it's true that this design is deeper why don't we see these coils anywhere?, there must be tradeoff's i assume with the design explaining why they aren't common?
Carl should know alot about these coils (or maybe not?) if anyone has built one feel free to chime in, if these coils are deeper (by how much extra depth could one expect?)
A mono would be easier to build, but a DD would be interesting, i would imagine the TX would be horizontal flatwound then the RX vertically wound, in my experience with my 5000 i have by much testing can get my 5 to run within an inch or two in depth as my 2200d in it's deepest setting, i like the DD design simply by how quite you can get them to run, so a DD like this could be an interesting build( not that i could do it (yet)).
So what say you?