On 2/21/2023 9:47 AM, David Needham wrote:
I came
up with that the impedance of the transmission line must be about 120 ohms
to get the approximate curves with the stock dimensions.
A pair of #12 THHN taped together is in the range of 105 ohms (two
colors to keep track of polarity). Twisting the pair would likely raise
Zo slightly. I see zero reason for a third conductor. With a line that
short, I would not expect Zo to be critical.
We've often used a C3SS when operating portable for CQP and 7QP county
activations, and found that it is very picky about chokes. It does like
the right number of turns of #12 THHN around a 2.4-in o. d. #31
Fair-Rite toroid.
73, Jim K9YC
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