8-band Windom antenna

The described 8-band Windom antenna allows operation on eight HF bands from 80 to 10m. The Windom antenna was developed in 1929 by W8GZ and its version labeled FD-4 has been used by radio amateurs for many years.

Another development, which first appeared in an old issue of the QRV magazine, added additional radiators, increasing the number of bands the antenna operates on. DL1BCC achieved excellent results by simply adding two wire elements with lengths of 4.69m and 9.38m to the FD-4, which he successfully verified in two years of operation.

The length of the radiator is calculated according to the formula: L/2 = 142.5/f, where it holds that if the element resonates, for example, at 30m, it will also resonate in the 15m band. The intention was not for the antenna to operate in the 18 and 24 MHz bands, but the antenna also works there, thus on eight bands.

Construction of the Windom antenna

The antenna requires a space of about 40m in length (note: Ivan OM2CS practically verified that the bending of the ends of the radiator is not very detrimental). In the case of DL1BCC, the suspension points are at a height of 8m, but due to the sag, the antenna is only about 6.9m above the ground at the lowest point. DJ7SH placed the antenna at a height of 5m, with part of the antenna going over the garage. Shorter radiators create an inverted V with an angle of about 100 degrees.

After stretching the antenna, first check if the antenna resonates in the 80m, 40m, and 20m bands. If necessary, adjust the length of the 27.7m section so that the antenna meets your requirements in these bands. You will likely notice that the resonance in the 30m band shifts slightly above the band.

When adjusting the antenna, be careful not to have the ends of the radiators twisted into a coil, as this would affect the antenna's properties. The feeder must be run vertically to the ground before leading to the equipment. DL1BCC placed the coaxial cable in an old garden hose to prevent damage.

The lower antenna height at DJ7SH did not require adjustment. But as seen in the PSV graphs, the tuning on 40m is quite bad and even the lowest PSV on other bands is higher. However, both stations can operate the antenna without any matching circuits.

Ivan OM2CS also successfully uses this antenna. Due to lack of space, he had to bend the ends of the radiator, yet the antenna works very well. Lowest PSV 80m - 1.05; 40m - 1.4; 30m - 1.2; 20m - 1.2; 17m - 1.1; 15m - 1.2; 12m - 1.3 and 10m - 1.1.

Finding the ideal all-band design

After the antenna was made, the first connections were established. The good efficiency was confirmed. Especially the lower part of the antenna (inv.V) contributed to a significant improvement in DX communication compared to a horizontal antenna. In the 30m band, a number of connections to the eastern and western coasts of the USA were made with reports of S6 and S7 at 100W. There were no noticeable differences in connections across Europe.

The description of this antenna is not scientific, but it provides an incentive for the implementation of a good antenna on multiple HF bands.

Literature:
[1] – Eine Doppel-Windom-Antenne fur acht Bander, Hubert DJ7SH and Rolf DL1BBC, CQ-DL 9/83

Thanks to Ivan OM2CS for the data