Yagi Antenna
The Yagi (Yagi-Uda) is a directional beam antenna: a driven element plus a reflector behind it and one or more directors in front. SimTX provides a 3-element and a 5-element version.
Configuration[edit | edit source]
The boom points along the configured azimuth; elements are horizontal. The driven element length defaults to 10.1 m; a value of 0 sizes the antenna for the operating frequency.
Characteristics[edit | edit source]
| Version | Typical gain | Typical takeoff angle |
|---|---|---|
| 3 elements | 7.5 dBi | 14° |
| 5 elements | 10.2 dBi | 10° |
- Strongly directional: most of the power goes toward the azimuth heading, with a large front-to-back advantage. Aim it at the target region; a misaimed Yagi is worse than a dipole.
- Low takeoff angles at reasonable heights make Yagis the tool of choice for long-distance work on the higher HF bands.
- Wider SWR bandwidth than simple wire antennas, the 5-element version widest.
Practical notes[edit | edit source]
- Set Azimuth to the great-circle bearing toward the target area (0 is north, 90 is east).
- A full-size Yagi for the low bands is enormous (a 3.6 MHz driven element is about 40 m); realistically they are used from roughly 14 MHz upward.
- Height still matters: mount at least half a wavelength up for the advertised low-angle performance.
When to use[edit | edit source]
For point-to-point and long-distance coverage toward a known direction on the higher bands. For all-around coverage use a Dipole Antenna, Vertical Antenna or Full-Wave Loop Antenna instead.