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The New Carolina Windom "The copyright for the
term 'Carolina Windom', as relates to the designs of Jim Wilkie
(WY4R), Edgar Lambert (WA4LVB), and Joe Wright (W4UEB), is owned by
Jim Thompson, (W4THU). All commercial use of the
term the term 'Carolina Windom' and commercial distribution of
'Carolina Windom' antennas is
reserved."
As with all ham stations QRO or QRP, ten percent of a station’s success in quality QSOs is the equipment and the operator. Ninety percent is the antenna. This is especially true in QRP since with very low power, by comparison to the Power Mongers, we need to get more ERP per watt out into the ether to be heard. So when I got back into QRP a few years ago I found the fascinating world of antennas and RF radiators to be an exciting challenge and a means to find the perfect antenna which I call the....New Carolina Windom.. I don’t have room for an 80-meter dipole or long wire so I have to restrict the length to 100 feet or less. Besides my primary interests are working only CW on 40, 30, 20, and 15 meters. Based upon these parameters, I have found what I consider to be the perfect antenna. The antenna I will show you how to build in this article evolved from a concept that had its beginning back in 1929 when Loren G. Windom described his invention in the September issue of QST, 1929, pages 19-22. Just do a search on Google for more on the "Windom".A few years ago, three hams, Jim Wilkie (WY4R), Edgar Lambert (WA4LVB), and Joe Wright (W4UEB), came up with an idea for an off-center fed dipole that carried Windom’s single feed line antenna to the next level. It has since become known as the Carolina Windom. I will call this the Traditional Carolina Windom since it was the first attempt at creating this specific type of multi-band antenna based loosely on Windom’s original concept. The differences between the New Carolina Windom antenna and Windom’s original is that the Original Windom is not a dipole. Enter the New Carolina Windom
For one, the 4:1 Balun has been moved to the antenna radiator and is built into the center insulator. The other interesting feature is that the 10 feet of coax from the Balun is terminated in a choke or line isolator. I have fitted the 10 foot stub with PL-259 UHF connectors on each end. This allows the coax vertical radiator to be easily removed if desired. It is designed to hang vertically which is one reason why this antenna is so effective. The radiation pattern when using the vertical radiator combines both horizontal and vertical radiation components and lowers the effective angle of radiation getting more of your signal near the horizon. This antenna is in use the world over by DX'ers and DX'peditions. In one Navassa DX'pedition, of the 33,000 QSOs made, more than 27,000 were accomplished with this antenna. The DX'pedition team also had a beam and verticals, but the New Carolina Windom was the antenna they used. Its reputation for excellent performance is so good that it served as one of the antennas in setting two 40 meter "mile-per-watt" world records of nearly 4,000,000 miles-per watt.The antenna can be used without the vertical radiator but the radiation pattern will lose the low angle component and may make the antenna less effective. If the vertical radiator is removed then you should move the line isolator to the bottom of the balun. NOTE: This antenna should not need a tuner on the 40, 20, 15, and 10 meter bands although you may use one if you feel the need to. It will operate on 80, 30, and 17 meters but will require a tuner for these bands. Here is the math for designing the New Carolina Windom
cut for your lowest band operation: 468 / 7.1mhz =
65.9 feet (round to 66 feet) for total half wave length. Using 3.9mhz (80/75 Meters)
Editors note: The New
Windom can be designed for 160, 80/75, or any fundamental frequency
you desire as the lowest band of operation and it should perform
better on that fundamental frequency and still resonates on the harmonically related bands
without a tuner. Just keep the original ratios (37.8% and
62.2%) the same by using the formula. If you are a
perfectionist, then you may want to trim ends for best SWR.
According to all who have build the New Windom using these formulas,
they work great! Get is up as high as possible and have
fun! Questions? Email Len at k4iwl@arrl.net Copyright notice: "The copyright for the term 'Carolina Windom', as relates to the designs of Jim Wilkie (WY4R), Edgar Lambert (WA4LVB), and Joe Wright (W4UEB), is owned by Jim Thompson, (W4THU). All commercial use of the term the term 'Carolina Windom' and commercial distribution of 'Carolina Windom' antennas is reserved." CAROLINA WINDOM AT RADIOWAVZ
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