Outdoor Window Mounted HF Helical Antennas

Outdoor Window Mounted HF Helical Antenna

By: Igor Grigorov, VA3ZNW

In the far 90s it was installed and tested several outdoor HF helical antennas. About two designs of the antennas is the article. The antennas were mounted on the clothes drier installed at the first floor of the 9 story building. Height from the ground to the clothes drier was near two meter.

Helical HF antenna for the 40- meter Band

The antenna was installed on the clothes drier and was placed near 70 cm out of the concrete wall of the house. Form of the antenna was made from wooden sticks. The sticks were fixed by the nails to the wooden triangles. Each side of the wooden tringle had length of 30- cm. Length of the sticks was 2.3- meter.

The length of the helix form was defined by the length of the window where the wooden form was mounted. Stranded copper wire in 40 meter length and in 1- mm diameter (18- AWG) was wound above the form.

Window Clothes Drier

Wire in 3- meter length going from the helix to transceiver and wire in 1.2- meter length going from the helix to the capacitive load as well was included to this length. Figure 1 shows design of the Window Mounted Helical Antenna.

Figure 1 Design of the Window Mounted Helical Antenna

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