Algorithms by Harold Wood
Input/Output Programming by George Gaman.
Handbook formulas use:
Length, Diameter, and Turns.
This program uses:
Length,
Diameter, Turns, Wire Size, Frequency, Coil Form Dielectric, Groove Depth,
considers skin effect,
proximity effect, distributed capacitance, coil form dielectric, groove
depth and wire material.
The results can be much different. For example, a loading coil for use at 3.9 MHz will have a handbook calculated value of 75 microhenries, vs 108 at the real-life operating frequency.
This is because the coil's distributed capacitance is in parallel with the coil's inductance, making the effective inductance of the coil higher and dependent on frequency. Many low-cost test instruments give the low-frequency inductance. An exception is the Autek RF1 LCR meter which gives the inductance at the specified operating frequency.
This program considers the effect of distributed capacitance, wire size, skin and proximity effects to calculate the real life or 'effective' inductance
at the specified operating frequency. Results include distributed capacitance and self-resonant frequency. At the specified operating frequency, inductance, reactance, resistance and Q are calculated.
This program is superior to all other coil programs in that a single digit
in any parameter can be changed, and the results are recalculated automatically.
This feature permits adjusting each parameter in turn to instantly see its
effect. This greatly speeds up the finding of the desired optiminum values.
Coil input data ranges are as follows:
Length, 0.25 - 120
inches
Diameter, 0.25 - 120 inches
Turns, 2 - 2000
Wire size, 1 - 40
AWG
Frequency, 0.1 -120 MHz
The accuracy has been checked using a
group of coils ranging in length from 0.5 to 10 inches, in diameter from 0.5 to
3 inches, and turns from 5 to 60, and wire sizes from AWG 12 to 30. Results were
compared against a Hewlett-Packard/Boonton 260-A Q-meter with
hermetically-sealed standards. Accuracy was within +/- five percent.
Comparisons between calculated and measured results are affected by length
and location of test leads and the proximity of metal objects.