At 06:15 11/01/00 +0100, you wrote:
Hello all,
Walter Staubach wrote:
....After realizing
my loop I found out, that the capacity of the loop itself between the turns
was already 800pF. That generates losses. Do you know that capacity in your
loop?
How can one measure the capacitance of the loop itself? Any suggestions?
73 Heinz, OE5EEP
By searching the 'self resonant frequency' of the loop :
1. use the loop without any external capasitors and look for the resonance
frequency (F1)
2. add a external capacitor (Cext) and look for the resonance frequency (F2)
The loop capacitance (Cint) can be calculated based on following formulas :
F1 = 1/(2*Pi*Sqrt(Cint*L)) and F2 = 1/(2*Pi*Sqrt((Cint+Cext)*L))
(where Pi = 3.1415... and Sqrt = square root)
This will lead you to
Cint = Cext * (F2*F2/(F2*F2-F1*F1))
73, Rik ON7YD
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