Natural balun/Antenna
Hi, Gurus -
Shown in "Antennas for All Applications" on page 820, figure 23-17 (a) is a
folded dipole which looks as if it could be easily constructed from RG58.
This antenna would be appealing because of the natural balun. However, they
make no mention of the required coax velocity factor nor of the terminal
impedance. I tried constructing one and measuring with a vector voltmeter
but the data were inconclusive. That is, I don't think I know how to make
measurements like this at 440 MHz yet. It is much trickier than I thought.
In any case, can someone tell me:
- Can RG58 be used, or will the velocity factor mess up the antenna?
- What will be the terminal impedance?
- Will the terminal impedance change as the gap between the elements vary?
(I consider the "terminal" at the midpoint of the bottom element)
Thanks.
John (KD5YI)
BTW, I can post a picture tomorrow or the next day, if necessary, when I can
lay hands on a computer with a scanner.
J
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