[Photo] FM three-unit Yagi antenna production
FM three unit Yagi antenna production: Follow WeChat Download Audiophile APP Follow the audiophile class related suggestion The story made by the engineer: The whole process of Niuren's homemade WIFI Shuangling antenna. This production refers to the drawings collected on the Internet. It is said that there is a gain of about 11DB ... This production refers to the drawings collected online. It is said that there is a gain of about 11DB, and the test is indeed true after completion. Yagi antenna is a kind of directional antenna, made by ... The distance between the feeding ends of the active elements of the antenna is about 5-10 mm. I did not add "ping ... FM-DV2 dipole antenna FM-DV3 dipole antenna frequency
The production material can be copper, aluminum or stainless steel with a diameter of 6 ~ 8mm. I chose the stainless steel tube that is the easiest to use. The whole antenna is shiny and shiny, very beautiful, and never rusty. Friends who are interested can try it.
The connection between the antenna and the feeder is a very important issue when installing the antenna. If the connection is incorrect, it will directly affect the receiving effect. The connection method depends on the shape of the active element in the antenna and the type of feeder. The following are commonly used.
1. The active oscillator of the antenna is a half-wave folded oscillator (impedance 300?‰).
When the 300?‰ flat feeder is used as the connection feeder, the connection method is the simplest, that is, the two wires of the feeder are connected to the middle opening of the active vibrator, as shown in Figure 1. If a 75?‰ coaxial cable is used as the connection feeder, the connection method needs to match the half-wave folded oscillator 300?‰ impedance transformation with the coaxial cable 75?‰. The method is to carry a 1 / 2-wavelength coaxial cable to make a U-shaped converter, as shown in Figure 2. First connect the two ends of the middle core wire of the 1 / 2?? coaxial cable to the opening of the half-wave folded dipole antenna, and connect the outer shielding network; the core wire of the main feeder connects to either end of the antenna opening, and the shielding network Connect the shielding net of U-shaped converter.
2. The active oscillator of the antenna is a half-wave oscillator (impedance 75?‰)
When the feeder adopts a 300?‰ flat feeder, impedance transformation is required. The method is to use two flat feeders of 1/4 wavelength to make an impedance converter. The connection method is shown in Figure 3.
When the feeder uses a 75?‰ coaxial cable, it only needs to perform balanced-unbalanced conversion, and a 75?‰ coaxial cable can be used as a U-shaped converter. The connection method is shown in Figure 4. Take a 1 / 2?? coaxial cable, connect the two ends to the antenna opening and connect the outer layer; then cut off at the U-shaped converter at 1 / 4??, and the core of the main feeder is connected at 1 / 4?? For the coaxial core wire, the outer shield wire is connected to the coaxial core wire at 3 / 4??.
In addition, it can also be made with a double-hole magnetic core. The production method is shown in Figure 5 (a) and (b).
The outstanding advantage of the dual-hole core impedance converter is its small frequency bandwidth, and its disadvantage is its poor anti-interference ability and selectivity. '+ data.username +'