Craig, NX1G/W1JCC wrote:
"I think I used the same core quadrafilar wound 3 wires in series for
primary, 1 wire secondary derived from K1VR article in 73 (remember that
mag?)"
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I believe 73 mag is still around, but I don't subscribe.
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"If you were gg to match the antenna to 75 coax, how many turns would
that be? I'm sure I cud figure it out but why "invent the wheel" when I
bet you already know."
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Using type 43 core material on 160m, I like to use about 10 turns for the
50 or 75 ohm "primary" winding. The "secondary" winding depends on the
impedance you want to match. If 450 ohms, and you're using 50-ohm coax,
that means the "secondary" should have 3 times as many turns as the
"primary" (the square root of the impedance ratio), or 30 turns in my
case.
For 75-ohm coax, the impedance ratio would be 450/75 = 6, or a turns
ratio of about 2.5 ("secondary" = 25 turns in my case).
Those who like to use 600 ohms for the feed impedance of a Beverage would
need an impedance transformation of 12 to 1 for 50-ohm coax (turns ratio
of about 3.5) or 8 to 1 for 75-ohm coax (turns ratio of about 2.8).
I like the "autoformer" type of design (single tapped winding) for
matching to the single-wire Beverage.
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"Is this a better design?"
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Whatever works, don't fix it.
73, de Earl, K6SE
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