High Q air core inductanne
In deigning air core the book mentioned for increasing and improving the quality factor of an air core we should close spaced windings. However, in another reference, as I remember,"The windings can be separated to reduce the inter-winding capacitance which in turn will increase the Q facotr"
Now, for high Q what should I do? make the space smaller or bigger?
Hi
If you're interested, I can send you a small java program for calculating air coils.
With the online coil calculator
http://hamwaves.com/antennas/inductance.html
you get the same results as with the java tool. I did a lot of 3D simulations (CST) to check the accuracy of the tools.
Both tools deliver the same results and are good enough for practical use.
Thanks niki for your prompt response
I wil be grateful if you send the program's download link. In addition, do you know which formula did those software use?
Air core Q is mainly limited by copper losses respectively skin effect. Inter winding capacitance and self resonance are not directly related to Q.
Design methods differ a lot depending on the frequency range. Low frequency coils take advantage from litz wire and special winding geometries.
Generally, there's no simple "formula" to calculate air core inductance. Existing formulas are purely empirical. 3D electromagnetic simulation is the way to get it exact.
I totally agree.
This is the reason for the java-tool. Of course not one simple formula, but many effects are taken into account.
If you are interested, test the tool and compare it with a reference design. I measured my coils and also simulated them with CST.
Some information from the development of the tool... (in german)
General rule of thumb for solenoids is to space the windings by one wire diameter (somewhere between 0.5d and 1.5d is usually fine).