We Live In Nanjing

  Chapter 42 Change a little Zhu

Spectrum analyzers are not unfamiliar. There are large and small ones. The large ones are as large and heavy as the old-fashioned oscilloscopes in the university physics laboratory. The small ones are as portable and light as Nintendo handhelds. The purpose of the spectrum analyzer is to detect radio signals. , It can accurately capture the invisible and shapeless electromagnetic waves in the air and display it with an oscilloscope.

   There is a wave at the frequency of 14MHZ, and there is a peak at the position of the horizontal axis of 14MHZ.

   There is a wave at the frequency of 144MHZ, and there is a peak at the position of the horizontal axis of 144MHZ.

  If there are several waves, there will be several peaks, double waves will have double peaks, and large waves will have peaks.

Soon the unscrupulous people brought the spectrum analyzer. Someone knocked on the door. Wang Ning hurried to open the door. Standing outside was a young man with disheveled hair, sweating and wearing blue short sleeves. With a shirt and **** shorts, this is the hapless guy who was called to help by an unscrupulous leader at night, holding a spectrum analyzer with wires entangled in his hands.

  Is a newcomer who has just graduated in the workplace and does not know how to refuse a job that does not belong to him.

  If he has the thick skin of Lao Bai, he should say "Ah, I'm sorry, Brother Wang, I'm busy...ah...ah..." when he receives the call.

  At the same time, there is a heavy breathing sound.

  No matter how unscrupulous leaders are now, they will retreat.

  Pharaoh may not even care about a young man, pay attention to his body, don’t indulge in it.

   "Brother Wang, I brought you the spectrum analyzer." The young man panted, holding such a large object and climbing eight floors, but he was exhausted enough, "Is that this?"

   "Oh, thank you! Yes, yes, that's it, Xiao Zhu, you can help a lot." Wang Ning quickly took the spectrum analyzer over, "Are you tired? Sit down and take a drink."

   "No way, thank you, Brother Wang." Xiao Zhu waved his hand, "If there is nothing wrong, I will go back first and see Brother Wang."

"See you tomorrow!"

  The young man quickly turned and went downstairs.

Wang Ning puts the white spectrum analyzer on the dining table in the living room. It is a circle larger than the Icom725 shortwave radio in the room. It has a white engineering plastic shell and comes with a handle. The left half of its operation panel is LCD. On the right half of the screen are neat English and number buttons.

   "What's this?" Mom came out of the kitchen and took off the apron around her waist. "You got another radio?"

  "Spectrum analyzer." Wang Ning replied, "Agilent, it's tens of thousands of dollars per unit."

   "No committee did it?" Mom asked, "Will you use this thing?"

   "I'm an expert." Wang Ning patted his chest, "Do you know when I first used the spectrum analyzer? The first time I operated this thing, it was still..."

  "At what time?" Zhao Bowen asked.

   "Twenty years ago." Wang Ning said.

   "Then you have rich experience." Zhao Bowen said, "Director Wang."

"No? I used the old HP spectrum analyzer to help China Unicom debug the paging station." Wang Ning said, "Test the phase difference between the two antennas of the paging station. Do you know that? Because there is phase between the two antennas. If it’s bad, it needs to be unified, so you have to use this thing to test it. That’s still the BP era."

   "Then when was the last time you used a spectrum analyzer?" Dad asked.

   "The last time was the first time."

  "Are you really a commissioner? Haven't touched a spectrum analyzer in 20 years?" Dad asked, "Why is commissionerless have waste like you? Why does the country raise worms like you?"

   "Go on, I just said that I didn't personally operate it, but I can't direct others to operate it?" Wang Ning said, "Old people are not allowed to fish?"

  He connected the power to the spectrum analyzer, turned on the switch, and the LCD screen lit up.

  The spectrum analyzer is more convenient to use than a radio station. The important point is that it does not need to be powered, and it can be used by plugging in a 220-volt household AC.

  It’s not like a radio station can only use direct current, so you have to keep a car battery in your home to play a radio station.

On the screen is a grid coordinate system, the X-axis is the signal frequency, and the Y-axis is the radiation intensity. An uneven yellow jagged line is restless in the coordinate system. The restless line means back noise, and back noise means that the radio cannot receive it. The rustle when the signal arrives, the snowflake when the TV has no signal, it may come from humans, or it may come from the natural world, or even from the cosmic microwave background radiation. In addition to the jagged noise at the bottom, there are several obvious raised peaks.

These crests are the signals captured by the spectrum analyzer. They may be broadcasts, walkie-talkies, or other radio stations. In modern society, radio waves are pervasive and ubiquitous. The frequency sweep capability of the spectrum analyzer can theoretically search for electromagnetic waves of all nearby frequencies. .

  Wang Ning started to set the basic parameters of the spectrum analyzer.

  Press the "AMPLITUDE" button on the right side of the operation panel. This word means "amplitude", which is actually the signal and radiation intensity, and the Y-axis parameters are set.

  Wang Ning set the Y-axis unit to dBμV.

Next, set the X-axis parameters-the monitoring range of the spectrum analyzer is the full frequency band, and a lot of messy unwanted signals will be searched. The Icom725 that Wang Ning needs to monitor is the Baiyang Icom725. The frequency of the Baiyang is 14 MHz. Therefore, Wang Ning needs to reduce the scope of monitoring.

  Press the "FREQUENCYCHANNEL" key on the operation panel. In the upper left corner of the button area, this word means channel. Press it to set the X-axis parameters, which is the frequency monitoring range of the spectrum analyzer.

   "Xiao Yang—!" Wang Ning asked, "It's 14 MHz, right?"

"right!"

  Wang Ning narrowed the monitoring range of the spectrum analyzer to 5 MHz to 50 MHz.

  "Xiao Yang! Press PTT to try!"

  Poplar hears the news and presses the hand microphone.

  The Icom725 transmitter on the desk sends out signals.

  White Poplar didn’t speak, so what the radio sent out was an unmodulated carrier wave, just a piece of meaningless electromagnetic radiation.

   Immediately, the waveform on the display of the spectrum analyzer in the living room climbed rapidly, forming a small crest, at the position of 14 MHz, it was undoubtedly the radio signal of Baiyang.

"Look, this is Xiao Yang's signal." Wang Ning pointed to the wave crest on the screen. "Although it is a bit weak, it is obvious that at a frequency of about 14.255 MHz, we will do this later, and wait for Xiao Yang and that. If the BG4MSR is connected, we will try to see if we can catch the signal from the other party. If we can catch it, it will be easy. We have a way to find the source of the signal."

   "What if you can't catch it?" Bai Zhen asked, "When you were monitoring before, you didn't hear the girl's voice, did you?"

  Wang Ning pondered for a long while.

   “It’s unlikely that we won’t be able to catch it. The signal that can be received by turning two or five is unreasonable. We can’t receive it. In case, I mean in case we can’t receive it—”

  "What does that mean?" Bai Zhen asked.

   "It means the spectrum analyzer is broken." Wang Ning said, "Let's let Xiao Zhu come over and replace it with a spectrum analyzer."

   "If you change a spectrum analyzer, you still can't receive it?"

   "Then let Xiao Zhu change another one." Wang Ning said.

  "If you change the spectrum analyzer all the way, you can't receive it?"

   "Then get a little Zhu."

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  (Author Jun's Gossip: This book belongs to the theater essay column work, so the length will not exceed 500,000 words.

  However, I estimate that the number of words in this book is about 400,000. Old readers should be used to this length. )

  (End of this chapter)