Why a YU7EF Yagi?
- 50-ohm feed without lossy matching circuits
- Broadband performance, which also provides tolerance for manufacturing tolerances and sensitivity to the surrounding environment
- Suitable mechanical dimensions
- Declared gain of 11.96 dBi and F/B ratio of 26.6 dB with a main boom length of 244 cm
Currently, amateur radio operators can choose from various Yagi antenna designs. Among the most popular are the DK7ZB, G0KSC, and DG7YBN Yagis. Each design has its own advantages and disadvantages.
- DK7ZB Yagis typically have a 28/50-ohm matching circuit, which makes them structurally more complex
- G0KSC Yagis are characterized by a complex radiator, which unnecessarily complicates the manufacturing process for smaller Yagi antennas
- DG7YBN Yagis feature a modern design with a curved radiator, which transforms the feed impedance to 50 ohms
The YU7EF Yagi has the simplest design. To ensure the antenna is easy to transport and set up even in portable conditions, I chose the 6-element version, the EF0206 Yagi, to familiarize myself with this type of antenna.
The entire antenna, with the exception of the radiator box, was made from leftover parts from other antennas. The 20 x 20 mm support boom consists of two parts. The center box is plastic, type Z54. The connector is an N-type. The connection between the connector and the radiator is made with a very short coaxial cable.
Symmetrization is not implemented; several ferrite beads will be clipped onto the 50-ohm coaxial feed cable, which should eliminate reverse currents.
The elements are attached to the support boom using plastic mounts and clamps. The antenna is lightweight, and I believe it will perform excellently.
YU7EF 144 MHz Yagi
Construction of the YU7EF 144 MHz Yagi