Hi Brian,
I do not pretend to be any sort of expert here, so I have probably missed something vital.
But in your 2nd iteration, I notice the coil length is significantly longer (156.8mm vs 80mm) with the same coil diameter (37.5mm) yet the inductance remains the same at 97.8uH.
Surely the inductance should increase.
Even if the coil windings were spaced in the 2nd iteration, the Wire Length indicates just more turns as do the Turns (105 vs 79).
And finally, the Resistance (of the winding?) for the 2nd iteration is lower than the 1st despite using a longer length of wire (6 vs 7.39).
Just wondering...
Cheers...Bob VK2ZRE
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On 6/07/2023 6:30 am, Brian Beezley wrote:
On Wed, Jul 5, 2023 at 12:30 PM, alan victor wrote:
Second, in looking at your solenoid coil, the L/D ratio looks wrong for
optimum Q. Something like L/D of 0.5 to 1 per Terman is better served for Q.
Rules of thumb are handy, but today it's easy to directly optimize a coil design. The first image show's Mike's coil. The second shows it after optimizing turns and coil length. The third is after optimizing turns, coil length, and coil diameter. Q could be further improved by using thicker wire. The optimizer uses the Differential Evolution algorithm.
I suspect that the dielectric loss of your coil is secondary.
Form loss shows the loss in the coil form as a percentage of total loss.
The coil program is here:
Brian
