Cylinder Coils?

[Tinkerer]

Tinkerer, yeah that would be good for us newbies for sure.
BUT, i keep hearing about how coils can be made better than what's mass produced, all you who are experienced in making your own coils, have you done extensive testing against these mass produced coils?
Let's say you build a 14in mono coil , you have multiple companies that have/had made this version coil, so to really prove your homemade coil is superior i would say you would need to test against at least 3 other versions and if your coil beats all 3 then average out that extra depth.
In my mind to be a worthwhile pursuit, i would expect a minimum of 4-6 inches better depth on a coin sized object, have you done these tests or has anyone else?, if not, then by what reasoning are these coils "better"?

If you look at it like that, I say: Just buy a Minelab detector and use a Minelab coil.

Why?
For some of us it is different. We enjoy tinkering with electronics. Usually it starts like that:
Phase 1:
We assemble a kit or repair a simple fault on a detector. It works. That makes us feel good. After a few like this, it becomes routine, kind of boring.
Phase 2:
We try to build a whole detector from a schematic. It is a challenge. When we get it working, we feel joy and satisfaction.
Phase 3:
We design our own detector and build it. After many trials and immense difficulties, vast amount of work and tribulations, we got it working. It does what we wanted. We find the first nugget or coin or unique relic with our own creation. Now we burst of joy. We feel on top of the world. The satisfaction is profound. We feel accomplished, alive. There are no more limits. The elation is such, that we feel that life is so good that it could not get any better.

Is that the end of it? Not by a long way. It is just the beginning. The real life is only starting.

[GeoMax]

https://coil32.net/online-calculators.html

Best selection of inductor calculators

There is also a fantastic coil calculator available for download on the same website suggested by Eddy71.

[Eddy71]

https://coil32.net/online-calculators.html

Best selection of inductor calculators

[Nova]

Damn Carl you are the optimum inspirationalist LOL!!! 1inch? no chunk is safe now, lookout goldfields i'm coming for you, with the extra inch i'm going to clean you out, i'm comin just you wait...................

[Carl-NC]

In my mind to be a worthwhile pursuit, i would expect a minimum of 4-6 inches better depth on a coin sized object

Wow, that's rather optimistic. I'd be OK with 1 extra inch.

[Nova]

Tinkerer, yeah that would be good for us newbies for sure.
BUT, i keep hearing about how coils can be made better than what's mass produced, all you who are experienced in making your own coils, have you done extensive testing against these mass produced coils?
Let's say you build a 14in mono coil , you have multiple companies that have/had made this version coil, so to really prove your homemade coil is superior i would say you would need to test against at least 3 other versions and if your coil beats all 3 then average out that extra depth.
In my mind to be a worthwhile pursuit, i would expect a minimum of 4-6 inches better depth on a coin sized object, have you done these tests or has anyone else?, if not, then by what reasoning are these coils "better"?

[Tinkerer]

MiscEl.zip

this app is old and does not update anymore, but it is very useful.

[Tinkerer]

It is true that the cable & shielding can have a dramatic effect on final performance, but it is still quite useful to compare raw windings. The table in post #6 contains very valuable information if you are trying to determine which type of winding (or wire) to use for an aggressively fast coil, or which winding style will give the most depth. In particular, field strength efficiency comparisons are little changed by shielding or cable impedance.

I can agree on that.
The fact is, that there are many factors involved in building the right coil for a specific kind of target. Compromises have to be made in the end.
Most amateurs just use an existing coil because they consider it to be too much work to build their own. Too complicated.

So maybe we should talk a bit more about coil building.
Discuss:
The reasons for a coil shape.
The diameter of the coil.
The type of wire to be used and why.
Thin wire or thick wire?
PVC or Teflon insulated?
The type of winding and the reasoning behind it. (as started in the discussion above)
Things like tight windings or loose windings. (Tighter windings have more inductance and capacitance)
Shielding types and materials
The importance of the distance of the shielding to the coil wires

I find the link to the MOGAMI website useful. There is an online calculator where you can compare the inductance and capacitance between wires for different diameters of wire, Teflon, PVC, air space between wires etc.

http://eve.mogami.com/e/cad/electrical.html

http://www.mogami.com/e/cad/coil-01.html

HyperPhysics

The misc.El app is also very useful for coil calculations

[Carl-NC]

Tests without the real cable and shielding, are quite useless, because the characteristics change dramatically when adding the shield and the cable.
The cable itself is of significant importance, as the wrong cable can spoil the whole coil.

It is true that the cable & shielding can have a dramatic effect on final performance, but it is still quite useful to compare raw windings. The table in post #6 contains very valuable information if you are trying to determine which type of winding (or wire) to use for an aggressively fast coil, or which winding style will give the most depth. In particular, field strength efficiency comparisons are little changed by shielding or cable impedance.

[Nova]

While it's fresh in my mind, i don't like the way the coil connection is on the box of the SD/GP/GPX detectors, it very awkward trying to push the connection into the box, i was thinking about a small dongle connection, one end permanently connected to the detector the other end sticking out a little (enough to make it easy to connect), but i know about the cable being important especially with it's length, but would say the combined length of say 5cm for this dongle upset the balance of the coils final characteristics? anyone?

[Nova]

Tinkerer, if that is the case, why bother with tests like this if they aren't going to give you an accurate result?, that part is nonsensical, if i had the time and knowledge of building these coils like a lot of you have on this forum i would do exactly that and then clean up the goldfields, and then after i had done that THEN i would give the secret away LOL!!!!

[Tinkerer]

Thanks for that Boilcoil, by what i can see "4" flat basket weave is the outright best on 300mm + ?, and the vertical flatwound "5" is 2nd, it would be interesting in knowing if this trend continues upto 400mm and beyond, maybe the vertical coil would catch up and beat it in the end, anyone know?, Carl?
Some of us aren't interested in chasing amoeba ****e, but are looking to chase 1oz+ chunks at 3-5ft deep, can a conclusion be determined on what really is the best coil for this and the size of course, but not forgetting the mineralised ground part of the equation? and on a Minelab, i have an SD2200d it is a couple of inches deeper than the 5000, BUT, the 5000 can be set to run very quite in hot ground, the 2200d is not so quite and also the signal response is far weaker,( newer tech definitely wins here), if i can get an even deeper pulse installed on the SD i would consider getting that done, anyone know if that is possible?

Tests without the real cable and shielding, are quite useless, because the characteristics change dramatically when adding the shield and the cable.
The cable itself is of significant importance, as the wrong cable can spoil the whole coil.

[Nova]

Thanks for that Boilcoil, by what i can see "4" flat basket weave is the outright best on 300mm + ?, and the vertical flatwound "5" is 2nd, it would be interesting in knowing if this trend continues upto 400mm and beyond, maybe the vertical coil would catch up and beat it in the end, anyone know?, Carl?
Some of us aren't interested in chasing amoeba ****e, but are looking to chase 1oz+ chunks at 3-5ft deep, can a conclusion be determined on what really is the best coil for this and the size of course, but not forgetting the mineralised ground part of the equation? and on a Minelab, i have an SD2200d it is a couple of inches deeper than the 5000, BUT, the 5000 can be set to run very quite in hot ground, the 2200d is not so quite and also the signal response is far weaker,( newer tech definitely wins here), if i can get an even deeper pulse installed on the SD i would consider getting that done, anyone know if that is possible?

[boilcoil]

Someone had posted here, on the forum, a table with experiments with different coils (Including with cylindrical coil).

PS:The results are like Karl's results .

[Carl-NC]

2, maybe 3 more weeks. Amazon.