Thankyou Charlie.
I got those Q numbers from
http://www.m0ukd.com/Calculators/air_core_inductor_calculator/
Maybe a decimal point was left out.
Jim,
I thought something was misleading you somewhere.
Be careful with online calculators. The one in the link uses pi out to 39
places (which might give the impression of accuracy), but omits many far
more critical, important, parameters. It is a very rough guess that might be
a mile off, even though the publisher implies accuracy. They would be better
off to just use "3.1" for Pi, and add in some more important things.
One way to evaluate an inductor calculator for design omissions is to see if
it asks for:
1.) Insulation thickness and type
2.) Turns spacing
3.) Form material
4.) Conductor size
5.) Form length
6.) Form diameter
That one grossly fails. It doesn't ask for several important things.
To check the calculator for function, start taking a large coil up higher in
frequency. If you get weird results like progressively increasing Q that
goes over 1000 for normal good conductors, extreme inductance values (like
values near whole Henries at HF and higher), the calculator is likely just
junk.
That one completely fails. It obviously does not consider turn-to-turn
capacitance, skin effect, materials, or internal resonances, because I can
"make" door bell wire inductors with Q's in the thousands and almost a Henry
of inductance on 50 MHz!!
Since it doesn't ask for enough things and obviously ignores many important
traits of inductors, it is unreliable. It might work in some cases by pure
luck, but who knows when it could be trusted!!
Things like that can send you down the wrong path, and cause you to start
giving out wrong numbers.
73 Tom
_________________
Topband Reflector
|