Quote:
Originally Posted by Mr. Ham
Antenna Comparisons:
An off center fed dipole works on the principal of harmonic's.
The ratio - 1/3 / 2/3 length using a true 4:1 balun causes the short end to act like a reflector..
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The short end is not a reflector, its just part of the overall length that makes the antenna resonant on the lowest bands. If you look at the voltage and current of the off center fed you will notice that it is identical to a center fed dipole on the lowest band of operation with an increasing amount of voltage and current peaks as the frequency increases. The off center feed just changes the feed point impedance to a higher value that basically stays the same on harmonic frequencies allowing the use of a current balun to convert it back down to something near 50 ohms so it can be fed with 50 ohm coax. But anyway, the OCFD is a great multi-band antenna !