Clone Chance Help

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In the flat spiral coil, each successive winding is further out from the first. Would this be the most optimal way to keep interwire capacitance at it's lowest?

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In the basket coil, the wires bundle together at the intersections, having the opposite effect of what you are trying to achieve.

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In the flat spiral coil, each successive winding is further out from the first. Would this be the most optimal way to keep interwire capacitance at it's lowest?

From what information I've been able to gather the answer seems to be yes, on another forum Aziz (sadly missed from this forum ) started a thread discussing this issue, and some experiments were tried and still being tested, ideally a continuous spiral, without any crossovers or the wires touching, IE a small space between the wire.

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Yes, Aziz was the man when it came to modelling coils. I wasn't aware he left forum.
In the flat spiral, the space between windings would be attained by using insulated multi- strand wire, the insulation providing the space.
But in the flat spiral coil picture above, 15pF interwire capacitance is pretty darn good, achieved with regular enamel wire.

[samii]

Hello
above image in pdf format
maybe someone can try to press copper pcb coil.


40cmcoil.pdf

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In the flat spiral, the space between windings would be attained by using insulated multi- strand wire, the insulation providing the space.
But in the flat spiral coil picture above, 15pF interwire capacitance is pretty darn good, achieved with regular enamel wire.

Yes its perplexing ins't it , 15 pF sounds pretty good,
Aziz's instructions was for complete physical separation between turns .

[6666]

Hello
above image in pdf format
maybe someone can try to press copper pcb coil.


[ATTACH]43511[/ATTACH]

Tesoro already make a pcb coil, got a picture here somewhere.

[samii]

sized 39 cm pdf format

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I find it interesting that Andys coil is apparently slow even though its a flat spiral wind
and the wires are apart
but when you look at another flat spiral wind it only has very low capacitance (15pF)
but the wires are close together.



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Tried calculating interwire capacitance of above coils. Got a small difference, wondering what I might be doing wrong. I've read winding spiral coil results in low capacitance but shielding adds a lot of capacitance. Other than some tests I've done these are the only ones that list values that I can remember. Does anyone know where a spiral coil listed values that suggested a low SRF or high capacitance? Including picture of the last coil test I did comparing flat vs basket coil. Low capacitance and shielding added very little.

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Tesoro already make a pcb coil, got a picture here somewhere.

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I counted 42 turns on tesoro coil.

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Tried calculating interwire capacitance of above coils. Got a small difference, wondering what I might be doing wrong. I've read winding spiral coil results in low capacitance but shielding adds a lot of capacitance. Other than some tests I've done these are the only ones that list values that I can remember. Does anyone know where a spiral coil listed values that suggested a low SRF or high capacitance? Including picture of the last coil test I did comparing flat vs basket coil. Low capacitance and shielding added very little.

I think the general consensus is flat spiral coil gives lowest possible interwire capacitance, I would be interested in the relationship between early sampling and self capacitance and damping resistor, assuming that you have a fast switch off tx driver circuit.

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An air gap between the windings(as in tesoro coil) is the best.

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The air gap appears to be half the diameter of the copper track. This might be a clue.

[samii]

https://webench.ti.com/wb5/LDC/#/spirals

can design special spiral coils by above link

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Nice