Chapter 69 The Wisdom of the Uncles
Over the following weekend, Bai Zhen and Wang Ning began designing the remote communication system.
To put it simply, it is to make BG4MSR use mobile phones.
This is important.
Mobile phones are much more immediacy and convenient than landlines; it's time to upgrade that girl's communication method.
"The technical logic is very clear, and it's not difficult to do." Wang Ning sat on the sofa, stroking his unshaven chin, "Fundamentally speaking, we only need to do one..."
"Relay." Bai Zhen sat opposite him.
"Yes, we only need one relay." Wang Ning nodded.
The so-called repeater is an extremely common and commonly used infrastructure in amateur radio.
As we all know, these days more people are playing with the UV band than with shortwave. To play with UV waves, you only need to spend a hundred yuan to buy a handheld radio on Taobao or JD.com. This thing is not much bigger than a mobile phone, small and exquisite, easy to carry, with a built-in flashlight, and the flashlight can blind your eyes by pressing two buttons. It does not require a heavy and clumsy base station like shortwave. However, the UV band has advantages and disadvantages. The frequencies of UHF and VHF are much higher than shortwave. Anyone who has studied high school physics knows that the higher the frequency, the shorter the wavelength; the shorter the wavelength, the weaker the ability to bypass obstacles.
Therefore, radio waves in the UV band are propagated within the line of sight. UV waves can only reach places that your eyes can see. If there are obstacles in the middle, the signal will be blocked.
It cannot reflect through the ionosphere like shortwave can.
But modern cities are full of tall buildings, buildings stacked one upon another, and obstacles are everywhere. How can people who use the UV band conduct long-distance communications?
So people started thinking - why not put a repeater somewhere high up?
This repeating system can be installed on a high tower, on a mountain top, or even on a satellite - it must be set up in a high place where everyone can see it - the UV band radio in the HAM's hand first sends the signal to the repeater, which then forwards it out through the latter.
The repeater stands high and can see far, so it can transmit signals to faraway places. Amateur satellites or the International Space Station are in orbits hundreds of kilometers high, and can even support intercontinental communications.
Such a forwarding system is called a relay station.
"Relay?" Bai Yang was confused. He didn't understand how to use the relay station to establish remote control. "How do I do it?"
"Xiao Yang, if you are asked to design a solution so that BG4MSR can use Guai Liangwu to contact us at a long distance, how would you do it?" Wang Ning asked him.
Bai Yang was stunned for a moment and thought for a few seconds.
"Uh... we should establish a radio communication link, so that the big and small... BG4MSR can transmit the signal to Icom725 over long distances, and then let 725 transmit it to us."
"Yes, the idea is correct." Wang Ning agreed, "But how do we do it specifically?"
"She should have a portable radio in her hand as a terminal for sending and receiving information." Bai Yang further imagined, "She sends the signal to Icom725 through the radio, and Icom725 then..."
At this point, Baiyang suddenly got stuck.
"Forward."
He realized that the role of 725 in the entire link at this time was forwarding. The girl's radio transmitted the signal to 725, and 725 then forwarded the signal to Bai Yang.
What can be done to turn 725 into a forwarding node?
All functions of an antique like Icom725 have to be implemented manually. To send a call, you have to press the button on the microphone, and to receive a call, you have to release the button on the microphone. How can this pressing and releasing process be operated remotely?
You are not a robot. You can run a thousand miles away and still keep one hand in the room to click buttons.
"725 can't do it alone." Bai Yang said slowly, "It definitely needs an external device. This external device can send and receive radio waves on its own, and can control the sending and receiving of 725 on the other hand. When there is information to be sent, it controls the 725 radio station to enter the sending state, and when there is information to be received, it controls the 725 radio station to enter the receiving state."
"You are very insightful, Xiao Yang." Wang Ning smiled, "Just as you thought, we need such a peripheral."
"This peripheral is a relay." said Dad.
"Yes, it's the relay." Wang Ning nodded. "Xiao Yang, do you know the structure and working principle of the relay station? The kind of pure analog relay station... We'd better use a pure analog relay station. Digital relay or digital-analog relay are a bit complicated. I'm afraid the girl over there can't handle it, and I'm also afraid that something too sophisticated can't last too long. The structure of the analog relay is so simple that you can DIY it yourself with two walkie-talkies."
"Because the basic structure of a repeater is two amateur radio stations connected back to back." Lao Bai took over his words and explained to Bai Yang, "The main components of a repeater are two base stations with a duplexer. If you use two independent antennas, you can save the duplexer. Its operation method is very simple, two base stations, one for receiving signals, and one for transmitting signals..."
Old White pointed at his son.
"For example, you are a handheld radio and I am a relay. When you talk to me, it is equivalent to sending a signal to me. My ears are the receiver and my mouth is the transmitter. I am made up of these two radios. When my ears hear what you say, I use my mouth to relay your words to Lao Wang. When Lao Wang talks to me, I can also relay Lao Wang's words to you. Do you understand?"
Bai Yang nodded thoughtfully.
"I can understand that, but why can it be remotely controlled?"
"Here's the key. Didn't you just say that you need an external device that can automatically control the transmission and reception of 725?" Wang Ning said, "It just so happens that the repeater operates automatically. Normally, no one is in charge of it."
"Some relay stations are on top of mountain tops, some are on high towers, and some are on satellites," Bai Zhen said. "So most relay stations are unmanned."
"This means it has a mechanism to automatically switch between sending and receiving." Wang Ning picked up the marker on the sofa and propped up a small whiteboard on his thighs. "This is the mechanism we need. We can use it to replace human hands to operate the send button on 725. Xiao Yang, take a look."
As he spoke, he drew a rectangular box on the whiteboard, and then drew two flat rectangles above and below in the box.
Write three small words "Receiver" in the small rectangle above and "Transmitter" in the one below.
Finally, use an arc to connect the two rectangles.
"This is a relay."
Wang Ning pointed to the large rectangle with a marker.
“It consists of two radio stations.”
Wang Ning pointed to the two small rectangles inside with a marker.
"Normally, once the upper receiver receives a signal, it will trigger the lower transmitter to turn on, and the transmitter will forward the signal. But if we disassemble this repeater and connect the receiver and transmitter to 725 separately..."
Wang Ning drew another square next to the relay station.
Then mark 725 in the box.
Then erase the arc, disconnect the two small boxes in the repeater, and connect them to 725 with straight lines.
"Then at this moment, once the receiver above receives the signal, it is no longer the transmitter that is triggered to turn on, but 725 - do you understand? The communication link will be like this: BG4MSR uses the handheld radio to send the signal to the receiver, the receiver controls 725 to enter the sending state, and 725 transmits the signal across time and space to us."
"Then what about we send a signal?" Bai Yang asked.
"That's the reverse reproduction of this process!" Wang Ning replied, "We transmit the signal through time and space to her 725. 725 receives the signal and triggers the transmitter below. The transmitter sends the signal to BG4MSR's handheld radio."
Finally, he drew a big circle with a big stroke of his brush to frame everything.
"The above is the basic logic of the entire link!"
Bai Yang stared at the picture on the whiteboard for a long time, and then looked at Wang Ning's hairless head, the latter's forehead seemed to be shining with the light of wisdom.
“That’s amazing.”
"In this process, the role played by 725 is no longer just a radio station." Dad said, "but a super-time and space antenna."
The technical logic has been sorted out.
Next comes making a plan.
"First, we need to determine the goal of the plan and decide what effect we want to achieve." Wang Ning picked up the marker on the sofa and turned the whiteboard over. He looked up at Lao Bai and said, "The first point is remote control, right?"
"Yes, remote control." Bai Zhen nodded. "We want to make sure that the MSR can communicate with us normally even if it is not in front of Guai Liangwu or sitting on the chair, but in the next room, outside the house, or even a few kilometers or more than ten kilometers away. This is the effect we want to achieve."
“What are the specific operational requirements?”
"It would be best if it could achieve the same effect as using a normal walkie-talkie," Bai Zhen replied. "She can hold the walkie-talkie and speak by pressing PTT."
"Okay, then the requirements are as follows... First, the person and the platform must be separated and remotely controlled. Second, the operation must be simple and easy to learn." Wang Ning nodded and wrote them down one by one on the whiteboard.
"There's... there's one more." Bai Yang raised his hand.
"Xiao Yang, you say."
"Do not cause damage or destruction to the radio station itself." Bai Yang reminded.
This is very important. No matter what Dad and Uncle Wang want to do, they cannot affect the Icom725 radio itself. They still don't know why this radio has the ability to communicate across time and space. To everyone, that old Icom725 is a black box. In this case, the wisest choice is not to touch it.
Previously, Bai Zhen, Wang Ning and Zhao Bowen had rashly dismantled the machine and opened the casing of the radio, but fortunately it did not cause any impact.
"Okay...thirdly, it cannot affect the normal operation of the radio station itself." Wang Ning took note.
Finally he held the whiteboard up so everyone else could see it.
The handwriting is sloppy but eye-catching.
First, the person and the stage are separated and remotely controlled!
Second, the operation is simple and easy to learn!
Third, it must not affect the normal operation of the radio station itself!
The above three points will be the framework they must follow when advancing the plan next. They will do their best to achieve this goal and upgrade the communication tools in BG4MSR's hands. When the expert team of the Amateur Radio Emergency Communication Command Center of Reverse the Future and Save the World is fully operational, the wisdom of the uncles will be invincible!
(End of this chapter)
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