Many radio amateurs use wire dipole antennas relatively low to the ground for the lower bands. This significantly degrades the properties of these antennas, as most of the energy radiates vertically upwards.The solution would be to raise the antenna to a greater height or use a different antenna. From the perspective of a low radiation angle, vertical antennas are interesting, but building at least a 20m high vertical (lambda/4 on 80m) is almost an unsolvable riddle.
The ARRL Antenna Handbook talks about two-element antennas 'a lot of music for little money'. By adding one element to a dipole low to the ground, we achieve a significant reduction in the radiation angle, thus significantly improving communication efficiency. Another advantage is the directivity of the antenna, advantageous impedance termination, and surprisingly, simplicity.
Inspiration can be the article 'Antennas' Yagi antenna for the 3.5 MHz band' published in the Radio Amateur Newsletter 1/1986. I simulated this antenna in the program MMANA, where I wanted to verify how the antenna will behave at different heights above the ground and whether it would be possible to achieve an impedance of 50 ohms at the feed point.
In the range of height from 10 to 20m above the ground, the resonant frequency changes only minimally, with increasing height, the impedance decreases. The optimal height appears to be 12 to 15m above the ground, where the antenna has an impedance of 50 ohms, bandwidth for PSV<2 about 100kHz. The front-to-back ratio is low, about 7 - 12dB, and gain (according to MMANA) about 9.1dBi. The last piece of information needs to be taken with caution, more than any 'mathematical' gain, what is interesting is that the energy no longer radiates vertically upwards, but much more towards the ground.
Let's move on to the antenna itself, which I counted in the SSB segment of the 80m band. The selected system was radiator - director with an element spacing of 7.74mThis distance is not ideal for achieving the best parameters, but it allows for easy antenna implementation. The radiator has 2x 20.03m (total 40.06m) and the director 38.07mThe thickness of the conductors is 2mm. The antenna is powered through balun 1:1.
The construction of the antenna is simple. We will need about 80m of wire, a 1:1 balun, four insulators, and thin steel ropes (e.g. 3mm), the length of which we choose according to the placement of the suspension points. These ropes are light and have excellent strength.
According to the drawing, we will make the radiator and director and attach climbing ropes to the insulators to define the spacing between the elements and hangers. We need four points at the same height for hanging. These can be trees above a meadow or adjacent apartment buildings. Due to the small spacing, it is possible to mount the bracket on a family house.
Tuning should not be necessary. At a height of 10 - 15m above the ground, the minimum SWR should be below 1.3 (even 1.0). At a greater height, we will increase the spacing between elements, otherwise the impedance will be too low.