I'd like to share some of the information I've learned. Please feel free to correct me and provide feedback.
1. The natural resonant impedance of the array, when converted to a single equivalent impedance, is approximately 300 ohms, while that of the dipole array is approximately 50 ohms (theoretically, it's 75 ohms).
2. Ferrite and Balun: My understanding is that these are used to further reduce standing wave and improve efficiency. However, they are not strictly necessary.
3. The design with shorter unit lengths provides higher gain and a narrower bandwidth, primarily for ease of manufacturing.
4. Center-to-center spacing.
5. The main source of differences should be the way you connect your feed lines to the antenna array: Ideally, the feed lines should be directly connected to the array, without any extended wires (as shown in the example).
6. The signal strength may depend on the distance to the repeater. If it's too close, the difference might be small. Try using a more distant repeater. I was able to reach a repeater over 140km away with a 3-element Yagi antenna (with some echo, but not full communication).
闽ICP备2021006864号-7
闽公网安备35020602002794号