Litz Wire Coil

[6666]

6666 i've learned that coils have to be winded clockwise. I see u do the opposite. Did i learned wrong???

I have not heard that rule before for a PI mono coil, I always wind in the same direction . Transformers can be different. Concentric coils with feedback nulling is also different

[dbanner]

I don't think direction is important since field should radiate in both planes, the hookup is, besides, winding coils clockwise seems intuitive for a right hander?

[dbanner]

Especially for those of us who remember winding up those old time wrist watches

[ionut_mtb]

Somewhere in my head i had this information stored loooong loong time ago ))

[Altra]

If you compare a round random bunch wind coil to a flat spiral you should notice a increase in sensitivity to small objects , small coins etc also if your machine is good at detecting gold IE gold nuggets there should be a increase in sensitivity to small nuggets, ESPECIALLY if you stack the windings IE 15x15 rather than 30 turns.
They are actually quite easy to make and a number of different ways with former or none, keep the resistance low, adjust number of top stack for the required inductance.
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Thanks for the info.

I'm going to try pvc insulated, twin lead, speaker wire or lamp cord. I recall someone on the forum doing this in the past. It seems you could use super glue as turns are added. People using the Evolution coils report good results, so there must be something to it.

[James]

I have one more question, if you wind a spiral coil using speaker wire should the windings around the former be horizontal or keep the wire vertical to the horizontal plane. Thanks so much. Best to all Jim

[green]

Double sided tape. I just made it yesterday in about 10minutes

Tried with double sided tape. Compared with flat basket I've been winding, no lead wires. Shielded top and bottom with graphite paint, 2mm craft foam spacer top and bottom. Flat basket slightly better, probably no difference with added lead wires.

James, Haven't tried with speaker wire, I would try with the 2 wires vertical, minimum radial width.

[James]

I think I uploaded a picture of the new basket weave coil. it is made on G-10 board. I measure 224 uh, resistance of 1.2 ohms. I tested the coil in free space, detected a gold ring at 20.5 cm to 24.5 cm. I found holding the ring different ways gave the 2 results. Best to all Jim, I do think I will try the speaker wire coil

[6666]

I do think I will try the speaker wire coil

short the ends

[James]

Thank you for the info, Best to all Jim

[6666]

short the ends

Just to be clear on this
when I said short the ends, if you use figure 8 speaker wire cable
you will have two parallel wires from one end to the other
at each end of the cable twist the two wires together
so you will have a separate join at both ends of the cable,
this makes the coil one thick wire.

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[Chiv]

just reading this about speaker wire, I built a mono 40cm in dia with a half second winding on top of the first to use up the right length of cable to get my 350uh for my barra build. whell ended up with a real heavy coil (no need for the jim after swinging in around) but very fast response. ended up been 296uh at the coil and time I added my 2m of lead it come to 454uh, the good old air test with plenty of emi every where I'm getting 85cm on pliers and 35cm on 9crt ring. but its real heavy so was looking at building a litz coil to make a lighter one. one thing wether it the heaver wire or just the way it worked out , but the damping resister was a real low one(230ohms) compared to my mono bunch wrap 385uh using (670ohms). the other thing is that not much stuck to the pvc insulation while winding the coil hold for a bit then it let go after a few days, end up with glue gun to hold it together and then sandwich it together in 20lts bucket lids

[ionut_mtb]

Tried with double sided tape. Compared with flat basket I've been winding, no lead wires. Shielded top and bottom with graphite paint, 2mm craft foam spacer top and bottom. Flat basket slightly better, probably no difference with added lead wires.

James, Haven't tried with speaker wire, I would try with the 2 wires vertical, minimum radial width.

Thanks Green! Did you tried 3dss coil from chance pi thread?

[green]

Thanks Green! Did you tried 3dss coil from chance pi thread?

No. When I started making coils I had a large spool of awg28 solid magnet wire I wanted to use if I could. Tried a bundle coil first, wanted to make something faster. Tried to wind a flat spiral without success. Flat basket looked about the same, flat spiral wrapped around tooth picks. That worked so that is what I've been using. Didn't think the 3DSS coil would be any faster(lead wires have more capacitance than the coil I was using) so I didn't try one, plus I would have to make a form. The flat basket requires a reusable form. Thinking about making a larger IB coil so thought I would try a flat spiral again after reading your reply. Worked good but it did take longer than 10 minutes wrapping the awg28 solid wire, my vision not the best.

[ionut_mtb]

No. When I started making coils I had a large spool of awg28 solid magnet wire I wanted to use if I could. Tried a bundle coil first, wanted to make something faster. Tried to wind a flat spiral without success. Flat basket looked about the same, flat spiral wrapped around tooth picks. That worked so that is what I've been using. Didn't think the 3DSS coil would be any faster(lead wires have more capacitance than the coil I was using) so I didn't try one, plus I would have to make a form. The flat basket requires a reusable form. Thinking about making a larger IB coil so thought I would try a flat spiral again after reading your reply. Worked good but it did take longer than 10 minutes wrapping the awg28 solid wire, my vision not the best.

If you want faster coil most important is to use good quality wire - teflon silver plated stranded wire, and then see what arrangement works best. but is not cheap. And most important, setting up the detector correctly for the targets you seek.