I borrowed a coil from QCoil Inductors to measure with my HP 4342A Q meter.
This coil did not have the black, UV-resistant dielectric spreaders of
production coils, but it was otherwise the same. Here's what I tested:
23 turns #10 wire
Coil length = 6.25"
Coil diameter = 3.625"
Length of each #10 lead = 4.25"
All dimensions are wire center to wire center. I supported the coil
horizontally above the 4342A by its leads. The side of the coil nearest
the 4342A enclosure was 3.25" above it.
Measurements followed by results from coil.exe:
MHz Q uH Calculated
1.8 580 22.6 547 22.4
3.7 730 23.7 753 23.5
The 3.7 MHz measurement was highly sensitive to my hands on the Q meter.
I positioned them for maximum Q. I figured that current through lossy
flesh can only reduce Q.
I modeled annealed copper wire. The wire was very stiff. Calculated Q
for hard-drawn copper was 536 and 739. At these frequencies the
dielectric composition of the four 0.25 rods I modeled embedding the
turns (Air Dux style) had virtually no effect.
https://qcoil.net
https://k6sti.neocities.org/coil.htm
Brian
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