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I'm afraid you are hopelessly mixed up.
What on Earth has it got to do with RG58? As I have already said, using the well known formulae - Calculate C pF/m Calculate L uH/m Insert L and C in Zo = Sqrt(L/C) and Bingo! Zo = 3243 ohms. What it has to do with RG58 is as follows: C = 55.5 / (Ln( 2 * H / D ) - 1) picofarads per meter. RG58 has 93.5 pF/meter. (from ARRL Antenna Book) L = Square( N * Pi * D ) / 10 microhenrys per meter. RG58 has 258 nH/meter. (from Zo=sqrt(L/C) and Zo from ARRL Antenna Book) TransLine impedance, Zo = Sqrt( L / C ) ohms. RG58 is sqrt(L/C) = 52.5 Ohms. Propagation Velocity = 1 / Sqrt( L * C ) metres per second. Vp = 1/sqrt(L*C) = 203.7 m/s Take a length of H =1.5 metres of this helix and use it as a short vertical antenna above a good ground. It will resonate as a 1/4-wave vertical at 3.5 MHz. Using a 1 meter length of RG58, it will resonate at f = 1/(2*pi*sqrt(L*C)) = 32.4 MHz. Zo = 3243 ohms. Zo = 52.5 Ohms. Velocity factor = 0.0701 Velocity factor = 203.6/300 = .68 In other words, Reg, I don't see why I can't apply the same equations to determine the resonant frequency of a piece of RG58. Are you saying you can use these equations and I can't? After all, you are implying you can analyze your distributed coil/transmission line using non-distributed, lumped components. If you can explain my error, please do so rather than insulting me by saying I am hopelessly mixed up. |
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