What is the purpose of feeding an off-center-fed dipole (OCFD) between the center and one end instead of at the midpoint?

An ordinary center-fed half-wave dipole has a low impedance (about 72 ohms) at its fundamental frequency, but a very high impedance at its even harmonics. By moving the feed point away from the center (typically about 1/3 of the way from one end), the impedance characteristics at the feed point change significantly. At this specific off-center point, the antenna provides a moderately high but consistent feed point impedance (often around 200 to 300 ohms) across several harmonically related bands. This allows the use of a single impedance matching device, such as a 4:1 balun, to achieve a good match on multiple bands. Distractors suggesting that off-center feeding reduces common-mode current or magically resonates over a wider range are incorrect; in fact, off-center feeding often increases the risk of common-mode currents, making a high-quality current balun essential for proper operation.