Several people queried me as to what I meant by a K1XX Nonsynchronous
balun -- to transition between the use of 75 ohm hardline and my
Cusuhcraft 40-2CD.
It is described in the now defunct magazine Ham Radio, September 1978, p.
31.
Here is a quick summary:
Start at your transmitter, at 50 ohms.
Next, 0.0815 wavelengths of 75 ohm coax (usually RG-11).
Next, 0.0815 wavelengths of 50 ohm coax (usually RG-213).
Next , ANY length of 75 ohm hardline.
Next , 0.0815 wavelengths of 50 ohm coax (usually RG-213).
Next, 0.0815 wavelengths of 75 ohm coax (usually RG-11).
Now your 50 ohm antenna.
Be sure to use the correct velocity factor for your RG-11 and RG-213:
solid poly = .66
Belden foam= .78
PTFE = .80
Fred Hopengarten, K1VR
Six Willarch Road * Lincoln, MA 01773-5105 * 617/259-0088
e-mail: k1vr@juno.com
Big antennas, high in the sky, are better than small ones, low.
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