Ham Radio General Class Practice Test

What is the advantage of vertical stacking of horizontally polarized Yagi antennas?

1. Allows quick selection of vertical or horizontal polarization

2. Allows simultaneous vertical and horizontal polarization

3. Narrows the main lobe in azimuth

4. Narrows the main lobe in elevation

The correct answer is: Narrows the main lobe in elevation

Vertical stacking of horizontally polarized Yagi antennas primarily provides a significant advantage in narrowing the main lobe in elevation. When two or more antennas are stacked vertically, the resulting radiation pattern becomes more focused in the vertical plane, which effectively increases gain and directivity in the desired elevation angle. This narrowing of the main lobe enhances the overall performance during the reception or transmission of signals, as it reduces the influence of signals coming from unwanted elevation angles, improving the signal-to-noise ratio. Additionally, a more focused pattern helps in achieving greater distance and improving clarity when communicating over long distances, as the targeted elevation can be adjusted based on the stacking configuration. The other options relate to polarization but do not directly address the key benefit of vertical stacking, which enhances the specific elevation performance of the antenna system.