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Introduction:
After many people have successfully made directional antennas, their ambitions have grown larger and larger, because since an array of directional antennas has succeeded, why not make a double-row directional antenna? That ’s right! We just want a huge Ambition, moving towards the goal you want to achieve, so that our technology will improve, which is also the spirit of amateur radio players.
As long as you complete the experiment of the previous unit 144MHZ nine-section Yagi antenna, then you have to make a double-row directional antenna, it is never a difficult task. As long as you have a distributor, you want to make a few rows of directional antennas are no problem.
The two rows of directional antennas are merged, and there must be a distributor in the middle.
Precautions:
The length of the two ends of the distributor is preferably a quarter wavelength on an odd number of electrons. When you calculate the physical quarter wavelength antenna length (that is, the quarter wavelength algorithm described in the first unit), We also need to use this length to calculate the length of the quarter-wavelength on the electron, and use it in the length of the 75-ohm coaxial cable.
For example: the antenna frequency is 144MHZ, its quarter wavelength is 0.5 meters (physical), and the 75-ohm coaxial cable I use is RG-59, and the rate factor of RG-59 is 0.66 (75 ohm There are many specifications of coaxial cables, and their speed factors are also different, please refer to the factory specifications), so I have to multiply the 0.5 meter I just calculated and multiply it by 0.66, so find the quarter wavelength on the electronics The length is 0.33 meters. Suppose the length of the cable I need is 1.98 meters from the power supply point of the antenna to the T-connector. This length is exactly a quarter wavelength of 6 electrons, which is an even number, and we do n’t want an even number. Times, we need odd times, so we increase the length to 2.3 meters (this length is a quarter wavelength of 7 electrons), let it become odd times, such efficiency is the best.
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