Extended version of the W3DZZ-antenna
The antenna, shown in the drawing, is an extended version of the well-known W3DZZ-antenna, adapted for work on 160, 80, 40 and 10 m bands. For installation of the antenna it is necessary space about 67 meters.
The coaxial cable may have a resistance of 50 or 75 Ohms. Coils are wound on frame, made from plastic (you can use plastic water pipe for example), with a diameter 25 mm, with an isolated wire Ø1.0mm, turns to the turn (38 in total).
To mount capacitors can also be used a plate of fiberglass. The traps are connected to the antenna as shown in the figure.
In my case antenna hanged between two buildings with a height of about 27 meters. Antenna fed through a coaxial cable like RG-6U approx. 45 m long. With these conditions antenna provided a SWR not more than 1.5 at frequencies 1840 and 3580 kHz, and not more than 2 in the range 7 … 7.1 and 28.2 … 28.7 MHz.
The resonant frequency L1C1 and L2C2, measured with GDO before connecting to the antenna, was 3580 kHz.