"Thank...thank you."

Bai Yang and the other three stammered their thanks, and they were all shocked. Before they could say anything more, the waitress had already set the tableware, smiled slightly, and quickly retreated and disappeared.

Bai Yang finished the dinner without any danger, and after the evening self-study, he went straight home to ask questions. He wanted to know what these people said to the school, so the teachers looked at him and made him feel like he was a child.

Not much, but as soon as he got home, he found a group of people huddled in his bedroom chatting happily. Bai Yang was surprised

"Yes, yes, that's right, it's Zifeng Building. It only takes five minutes to walk there."

"Wait a moment, we are looking at the map."

"Look! Lao Wang, are you looking for a shortcut nearby?"

"How fast can that big eyeball move? Let's see if we can estimate a safe range..."

Bai Yang opened the door: "What are you doing?"

The three old men turned their heads as if they were thieves. Judging from their expressions, they thought they had been caught in a conspiracy.

"Chatting with the little girl."

Dad was holding the microphone, while Wang Ning and Zhao Bowen stood on either side of the chair, one holding a large map and the other holding a tablet.

"Have you already communicated with her?" Bai Yang was a little surprised. He looked at the time and saw that it had just reached eleven o'clock, "So early?"

"It's earlier than you think." Zhao Bowen said, "We connected three hours ago."

"BG4MSR, my son is back from school, let's talk next, OVER." Lao Bai happily gave up his seat and put his microphone on the table.

"Isn't this... only available after eleven o'clock? Why is it so early today? Three hours ago?" Bai Yang threw down his schoolbag and squeezed over, and the girl's clear voice sounded from the speaker of the I725 radio station: "BG4MXH? You are back.

?"

"It's me, I just came back, OVER." Bai Yang replied while holding down the microphone, then turned to ask his father, "What's going on? It's obviously not time yet?"

The experience of the past few months told them that this radio station can only connect to BG4MSR after 11 o'clock in the evening, and not at other times. It's not like Bai Yang has not experimented before. He specifically chose a weekend to connect to BG4MSR at 9 am and 12 noon.

, tried both at 6pm and 8pm, but neither succeeded.

Success can only be guaranteed if the call is made after 11pm.

"This is because our understanding of it has gone one step further." Zhao Bowen pointed to the radio station, "We have found indirect evidence that the black moon is an important factor influencing the communication across time and space."

"What kind of evidence?"

"The evidence is the frequency." Zhao Bowen replied, "This was originally just a conjecture. During the time when we took out the Guailiangwu for inspection, there were several conjectures within the team about the cause of the overtime communication.

Today we successfully verified one of them”

"I just can't stand your convoluted way of talking." Dad complained, "Can you get to the point?"

"I have to explain everything clearly, right?" Zhao Bowen rolled his eyes, "You can tell me if you have the ability."

"I'll tell you what I said!" Dad snorted, "Actually, the reason is very simple. The reason why we were able to contact BG4MSR in advance is because it was already there."

Bai Yang didn't understand what this meant.

"Yes, actually you can connect to BG4MSR at seven o'clock in the evening, all the time." Zhao Bowen interjected, "You don't have to wait until after eleven o'clock in the evening."

"But I tried it." Bai Yang was surprised, "It doesn't work at all!"

"Because your frequency is wrong." Dad said.

"14.255Mhz." Bai Yang said.

"At seven or eight o'clock in the evening, she was not on 14.255Mhz." Dad said, "This is the key."

Bai Yang was stunned.

"Then where is she?"

"About 14.305Mhz." Dad replied, "This is what we tried."

Bai Yang didn't believe it, so he decided to hold the microphone and ask directly: "BG4MSR, BG4MSR, let me ask you a question, do you adjust your radio frequency at night? OVER."

"FM?" the girl said, "No, I'm always on 14.255Mhz."

"Listen, she said she hasn't adjusted the frequency." Bai Yang leaned back in his chair.

"Of course she has not adjusted the frequency, but the change in frequency is not necessarily man-made." Zhao Bowen explained, "You know Doppler radar, right? According to the frequency change of radar waves, the flying speed of the target is measured. This principle is used in amateurs.

It is also often used in radio activities.”

"Play satellite." Bai Zhen said.

The so-called satellite shooting is a very common amateur radio activity. In addition to direct frequency communication, relay stations and ionospheric reflection, HAMs can also rely on artificial satellites in orbit to carry out amateur radio activities. This kind of relay is responsible for relaying amateur radio signals.

Radio signal satellites are called amateur satellites, such as the Lilac series satellites developed by Harbin Institute of Technology. Of course, the International Space Station is also a super-large amateur satellite (the International Space Station plays a very important role in the world amateur radio movement). Anyone can pass

Amateur satellites make long-distance calls, but it should be noted that amateur satellites are all low-orbit satellites. Unlike synchronous orbit satellites, low-orbit satellites will not remain relatively stationary with the ground. They will transit at a very fast speed. Once there is relative speed,

Then the Doppler effect of electromagnetic waves is an influencing factor that cannot be ignored.

When the satellite enters the country, the frequency of the electromagnetic waves being compressed will increase because the distance is rapidly shortening. When the satellite leaves the country, the distance is getting farther and the frequency of the electromagnetic waves being stretched will decrease. This principle is similar to standing in a train station and listening to the train.

The whistling sound at the station changes exactly the same.

Therefore, when a HAM hits a satellite, it must adjust its transmitting and receiving frequency according to the position of the satellite. This is called Doppler frequency shift.

"I know this."

Of course Bai Yang knows what the Doppler effect is, but he and BG4MSR are not communicating through satellite, so why are they affected by the Doppler effect?

"Don't worry, listen to us." Zhao Bowen said, "Based on the current experiments, we can get a preliminary conclusion. After about half past six, we can vaguely capture a little bit of signal, and after seven o'clock

, the signal was clear enough to allow normal calls. At that time, the frequency was 14.305Mhz, which was much higher than 14.255Mhz. Why is this?"

Bai Yang thought for a while.

"Is it because something is coming in?"

"In the latter half of the night, after 2 a.m., the optimal communication frequency will drop to 14.235Mhz. Why is this?"

Bai Yang thought for a while.

"Because something is leaving the country?"

"What exactly is entering and leaving the country?" Zhao Bowen asked, "If you think about this time, what will appear at 6:30 in the afternoon? It will stabilize at 12 o'clock in the evening? It will start again after 12 o'clock.

To distance yourself?"

Bai Yang slapped his head.

"Black Moon."

"Yes, this is the indirect evidence we have found. The change in the frequency of the radio station is consistent with the change in the position of the black moon. The black moon must be an important factor in the communication across time and space. This is the first strong evidence we have found."

Zhao Bowen said, "The speed of frequency change is almost 10Khz per hour. This frequency change is not small, so you cannot contact BG4MSR before 11 o'clock, and she is not within your reception range at that time."

Bai Yang understood.

He couldn't contact BG4MSR during the day because the black moon was not in the sky.

He couldn't contact BG4MSR before eleven o'clock because the frequency was not matched.

The bandwidth occupied by sending letters in SSB mode is very narrow (note that sending any information will occupy bandwidth. If a radio station sends letters on the frequency of 15.000Mhz, it actually occupies a frequency with 15.000Mhz as the midpoint, not 15.000Mhz.

One point), generally speaking, FM occupies the most bandwidth among various radio modulation methods. FM is greater than amplitude modulation, greater than SSB, greater than CW. CW is for sending telegrams. It occupies the smallest bandwidth, but CW can only tick. The advantage of SSB is that you

You can use it to make direct calls and the frequency band it occupies is very narrow. The SSB mode used by Bai Yang only occupies a bandwidth of about 20Khz. His transmission and reception are mainly concentrated in the narrow range of 14.255Mhz to 14.275Mhz. Once the other party's signal breaks out of this

range, he won't be able to receive it.

Taking 14.255Mhz at 12:00 midnight as the benchmark, and calculating at a frequency shift rate of 10Khz per hour, the frequency in the first half of the night will be higher than this number. The frequency of BG4MSR at 7:00 pm is 14.305Mhz, and the frequency of BG4MSR at 8:00 pm

It is 14.295Mhz. At nine o'clock in the evening, the frequency of BG4MSR was 14.285Mhz. It did not enter Baiyang's receivable range until ten o'clock in the evening.

This is the first time that Zhao Bowen and others have confirmed that the black moon has an important impact on overtime communication.

"Why does it have such an impact?" Bai Yang didn't understand. "The Black Moon is not a relay. The signal is not sent to the Black Moon. Why does it cause the Doppler effect?"

"Yes, you don't use directional antennas. You have to use Yagi to fly satellites. Black Moon is not a relay. This Doppler effect is not caused by the movement speed of Black Moon." Zhao Bowen nodded, "So

We speculate that its influence is at a deeper level. This conjecture is very bold... It was not me who proposed it. I am not that wild yet. It was a comrade from the Institute of Physics. He said that time and space itself are indivisible. Since the Black Moon affects

Time, then we cannot expect that space will not be affected. The Doppler effect of radio signals is only an external manifestation of the influence of the black moon on space..."

"What changes is actually not the frequency of the radio waves, but the space in which the radio waves are located." Zhao Bowen paused, "The black moon may be pulling and compressing space on a large scale."

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Chapter completed!