The distance between the feeding ends of the active elements of the antenna is about 5-10 mm. I did not add a "balanced-unbalanced" converter, and the 50-ohm coaxial cable was directly connected to the active vibrator. The horizontal oscillator impedance is about 73 ohms. The more passive elements of a Yagi antenna, the lower the input impedance will be. The 5EL 70cm band YAGI antenna made by 4RAE, the active vibrator is a folded vibrator (impedance 300 ohm), but the coaxial cable is directly connected to the feed end of the folded vibrator through a 1: 1 "balance-unbalance converter" . Made of 5EL YAGI, the effect is good after use. In June this year, with the BG4RAE in this band QSO, the signal 59.4 "balance-unbalance" converter is a kind of so-called sleeve-type "balance-unbalance" converter. In principle, a dipole antenna or a folded dipole antenna, when the feeder is a coaxial cable, a converter should be added to complete the unbalanced-balanced conversion of the feed, but the picture is simple when produced under amateur conditions. Can be used. For the structure of 4RAE's sleeve-type "balance-unbalance" converter, please refer to Figure 3. The YAGI antenna I made, the distance between the elements is equidistant, and the 4RAE is not equidistant. The same is the 5EL YAGI antenna, the total length is shorter than the size I give. From the analysis in the textbook, we know that the size of a YAGI is not unique. If the distance between the directors is longer, the directionality of the antenna will be stronger, but if the distance is too long, the gain will decrease and the antenna size will increase at the same time. Under normal circumstances, the distance between each oscillator is about 0.2 wavelength is more appropriate. I remember that there was a TV commercial that meant that it should be easy to use and beautiful. Finally, paint the finished antenna with green paint, just a little yellowish self-painting on hand, spray it randomly, and "wear" it with a camouflage suit. Figure 4 is an assembly diagram.

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