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This type of antenna is a popular antenna design as the performance is very good across the HF bands and requires little or no tuning. It’s a dipole fed off center with a 4:1 balun at the offset feed point. The antenna shown covers 80, 40, 20 and 10 meters.
7 lip 2020 · For this year’s ARRL Field Day event I was looking to put up a homebrew antenna that was easy to construct‚ easy to deplay‚ and give me multi-band support. I settled on an 80 meter Off Center Fed Dipole antenna. Watch the video to see how I do it:
23 paź 2011 · Here is a spreadsheet I designed in Microsoft Excel for calculating the first cut and the final cut (after testing) of a 1/2 wave dipole, whether center-fed, classic off-center-fed, Windom, or New Carolina Windom.
18 sty 2020 · An Off Center Fed Dipole is an easy way to use one antenna for multiple bands. The 80m version of the OCF Dipole is supposed to be capable of 80, 40, 20, and 10m bands. With a tuner, you are also supposed to be capable of using some of the WARC bands.
For an 80-10 meter OCF dipole antenna, divide the ½ wavelength standard of 468 by the lowest operating frequency of 3.6 MHz and you arrive at an overall length of 130'. This is the length of a standard dipole but instead of dividing the result in half, use a 36/64% offset to determine the feedpoint.
Let's find out by examining different offset feedpoints on an 80 M half-wave dipole for each amateur radio HF band. Offsets of 33%, 25% and 20% will be illustrated. The third harmonic of 3.5 MHz (3xf0) is 10.5 MHz but our amateur radio 30 M band allocation is a shade lower in frequency at 10.1 - 10.15 MHz.
Want to build a simple, efficient, multiband antenna? One of the best and inexpensive multiband antennas is the off-centre-fed (OCF) dipole. These are wonderfully simple antennas that permit multiband operation with little or no tuning. The OCF dipole does require a balun.
