We Live In Nanjing - Chapter 110

  Chapter 110 Martial Art’s Absolute Learning Is Coming into a Line

  What is the key to launching satellites?

   is tracking.

The entry and exit of the low-orbit satellites is also fast. They circle the earth in one or two hours, and the ground will pass overhead in one or two hours. The low-orbit reconnaissance satellite sent by Zhao and others to the future is only 300 kilometers in height. , Orbiting the earth in an hour, such a high speed will make Banxia face the same problem-this little thing runs too fast and is difficult to track, it is difficult to track and it is difficult to aim, and it is impossible to aim at it with an antenna. Difficult to receive data.

  ”Usually, when you hit satellites, how do you track the orbit of the satellite?” Bai Yang asked.

“Use software, such as SatOrbit, Heavens-Above, free of charge and free of charge, you can check the orbital parameters of all public satellites, when it appears and when it is over the top, which angle and direction are clear.” Wang Ning moved Sitting in the living room with a small bench, he is straightening the clothes hanger with a vise in his hand, “The professional one is STK, and similar software is everywhere, so that the satellites of the world no longer have privacy from you.”

  Obviously, in the era of BG4MSR, it is impossible to have these softwares. Humankind is completely extinct, there is no Internet, no servers, and no one maintains and updates.

“There must be no way for her to find the satellite orbit by herself. How can she find it? Let’s tell her here.” Bai Zhen also moved a small bench and sat in the living room, holding a vise in his hand. Hanger, “If luck is good, the satellite will re-enter orbit without deviation, then we will report the parameters here, and she will be able to align it soon.”

“In fact, the best plan is to bring a relay star over and place it on a synchronous orbit at an altitude of 36,000 kilometers.” Zhao Bowen also sat in the living room with a small bench in his hand. Holding a vise, cut and straighten a clothes hanger, “So that the relay star will always hang on top of the girl’s head. You don’t have to use your energy to track it, otherwise, if you hold a Yagi antenna on the top of the station and follow the satellite all the time, the spondylopathy will have to come out.”

   “Then you let them take a relay star.”

  Bai Zhen cut off the hanger in his hand with a click.

   “I **** mentioned it a long time ago, and I was scolded by the space crew.” Zhao Bowen pouted, “They told me, are you still a human? You are not a human!”

   “The result? Didn’t the relay star belt bring it?”

  Wang Ning also cut off the hanger in his hand with a click.

“I did, but they warned me that this will greatly increase the difficulty of orbit design, and at the same time greatly increase the probability of the satellite’s failure to re-orbit.” Zhao Bowen replied, “I said that there is no way, you can imagine a little girl Is Tian standing on the top of the building holding a Yagi antenna in circles? She doesn’t have to do anything else?”

The three old men sat around and chattered, the work in their hands kept on, just like the village women sitting together chatting, gossips and sweaters. How many gossips came out like this, but Bai Zhen, Wang Ning, Zhao Bowen San The individual’s hands are not knitting needles and wool, but vise and clothes hanger, with “clicks” one after another.

  As soon as Bai Yang went home from school in the afternoon, he saw them sitting together torturing the clothes rack and dividing the clothes rack by five horses. The scene was terrible, and I don’t know what the deep hatred was.

  What is this doing?

  This is making a Yagi antenna.

Yagi antennas are undoubtedly the most commonly used antenna type in the HAM community. Compared with ordinary rod antennas and dipole antennas, the advantages of Yagi antennas are high gain and high directionality. The signal is polarized in one direction. In layman’s terms, Other antennas are large light bulbs, and the light is scattered, and the Yagi antenna is a flashlight, and the light is only directed in one direction.

Due to the signal polarization characteristics of the Yagi antenna, it is also the antenna that HAMs often use to hit satellites. Because the power of ordinary amateur radio stations is very low, and the power of satellites is lower, the radio station and the satellite are like a dumb talking to a deaf person. They are still thousands of miles away-under normal circumstances, it is impossible for them to hear each other, unless the dumb masters martial arts skills to force the sound into a line.

  This perturbation line is the Yagi antenna.

  Bai Zhen put down the clothes rack in his hand, and picked up a long slender wooden board from the floor. I don’t know which furniture factory he picked up from the scraps, it was probably more than one meter long.

  ”What is the uplink and downlink frequency of that relay satellite?”

  ”Upstream 144MHZ, downstream 430MHZ.” Zhao Bowen replied.

   “The U-band transmission speed is a bit slow, so you can get an X-band.” Wang Ning said.

“The X-band reception is complicated. There is an X-band connection between the reconnaissance satellite and the relay satellite. The relay satellite can store the data and send it back to the earth slowly. Don’t worry about this.” Zhao Bowen picked up the measuring tape from the coffee table. How long is the reflector?”

  ”Upstream two-meter waves, the length of the reflector is one meter, and one-half of the wavelength.”

  Bai Zhen took the tape measure and measured the length of one meter on the straightened drying rack: “No, this drying rack is not big enough, less than one meter, is there a bigger drying rack?”

  Mom came out of the kitchen: “The drying racks at home have all been ruined by you.”

   “I will ask Xiao Zhu to buy a large one.”

  Wang Ning dialed the phone as he spoke.

  This evening, Xiao Zhu ran all over the supermarkets in Qinhuai District.

When the drying rack is straightened, it is the metal wire. Bai Zhen cut out a one-meter-long metal wire and used it as the reflector of the Yagi antenna. The structure of the Yagi antenna is so simple that it can be made with wooden strips and a drying rack. The reason why Bai Zhen and others chose Yagi is that it can take materials from anywhere, the method is simple, and it is extremely friendly to novices.

  Wooden strips are used as the central axis, and five straightened drying racks are placed vertically on the wooden strips in turn. They look like fish bones and form a plump shape, which is a simple five-element Yagi antenna.

  The rearmost and longest drying rack is called a reflector, which is responsible for gathering signals, just like a mercury bowl in a flashlight.

  The penultimate drying rack is called the vibrator. The **** is the core of all antennas. It is the signal source, and the electric current generates electromagnetic waves on the vibrator.

  The remaining three drying racks are called directors. They guide the radiation direction of the radio wave and let it radiate in the direction the antenna points to achieve the purpose of pointing where to hit.

  ”Do you teach her to do it after you finish it?” Bai Yang sat aside and watched the three of them do handwork. Hand rubbing the Yagi antenna is the basic skill of the old HAM, Zhao Bowen has almost forgotten, the old father and old Wang’s craftsmanship are not yet unfamiliar.

  ”When we confirm that this thing will work, let her copy the same one over there.” Dad replied, “Make do with it.”

   “This is simple, you can learn it as soon as you learn it.” Zhao Bowen said, “With the Yagi antenna, she can receive the signal from the satellite, and then pass it to us, planning and planning.”

  ”How long is the vibrator?”

   “96 cm, or 97 cm, look at the cut.”

   “The remaining three are the same length.”

   “Both are 88 cm.”

  ”Pay attention to the spacing. Should we have higher gain or better frequency band characteristics?”

  ”Try them all. After you’re done, take them to play AO-91, and try to see how it works…Also, pay attention to adjusting the impedance.”

   “50 Euro with eyes closed.”

   “Who of you brought the SWR instrument?”

   “It’s okay, I will let Xiao Zhu bring one over!”

The trio finally completed a UV double-segment Yagi. They carried this thing up and pointed it as if they were carrying a machine gun—Banxia also thought so. When she finished the Yagi two days later, she felt this The thing waved like the Fangtian halberd used by Lu Bu Ma Zhong.

  (End of this chapter)