The paper trembled, and Chen Hao's finger froze in mid-air. He didn't pull his hand back or reach for the paper; he just stared at it. It seemed to have been moved by the wind, but there was no wind in the lab.
Susan reached out and pulled the file away, slipping it into her notebook. "Don't just stand there," she said. "That jolt just now might have been a sign that the printer was about to jam."
Nana stood behind the terminal, the optical lens pointing towards the table. "A slight vibration waveform was detected, originating from ground conduction, lasting 0.4 seconds." She paused, "Most likely caused by the construction team next door moving metal frames."
Carl looked down at his legs, then looked up again: "It wasn't me."
Chen Hao finally withdrew his hand and rubbed his face. "Alright, let's take it as a good omen—our communications project will officially start to take off from today."
He walked to the whiteboard and looked at the goals he had written down yesterday: **Increase coverage radius to 15 kilometers, reduce blind spots by 80%**. The handwriting was a little crooked, and a bit of ink had leaked from the ballpoint pen in the corner.
"Let's get down to business now." He turned around. "Of the draft agreement you prepared last night, which path is the most reliable?"
Susan opened her notebook and pulled out several printed diagrams, laying them out on the workbench. One was a terrain profile, and the other showed a signal attenuation curve. "Simply changing the software won't work," she said. "The antennas we're using now are too weak; no matter how powerful they are, they won't transmit far. It's like trying to shine a flashlight into a ravine—the light is completely blocked."
Chen Hao nodded: "So we need to change the light bulb?"
“Changing the lampshade would be more accurate.” She pointed to the diagram. “The existing antenna is omnidirectional, so the energy is scattered and it can’t reach far. If we change it to a directional high-gain antenna, we can concentrate the signal into a beam and push it in a fixed direction, which can penetrate into the canyon.”
Nana responded immediately: "Database match successful. Three feasible structures: Yagi antenna, parabolic reflector, and patch array. Considering weight and material limitations, we recommend using a micro patch array."
Carl pulled out a ruler and drew a small square on the paper. "You can cut out the substrate from recycled circuit boards, and then wrap the copper wire around it a few times. The difficulty is that the feed point needs to be accurately positioned; even a millimeter's difference can cause the signal to deviate."
"Isn't that just manual work?" Chen Hao said. "You guys do the design, I'll just chant some incantation to make sure you don't solder it backwards."
Susan ignored him and continued, "Simply changing the antenna isn't enough. The signal also needs to be audible over there. I checked the data, and qpSK modulation is more efficient and has stronger anti-interference capabilities than the current FSK."
"Speak like a human being." Chen Hao leaned against the table.
"Simply put, sending signals now is like sending a telegram, tick-tock, which is easy to misunderstand. qpSK is equivalent to sending four states at once, doubling the amount of information and also correcting errors."
Nana simultaneously projected a set of data charts. "The simulation results show that, under the current noisy environment, qpSK combined with adaptive coding can reduce the bit error rate to 0.12%, and increase the estimated transmission distance by 4.7 kilometers."
Chen Hao whistled: "You're almost as fast as I can run."
Carl frowned: "Hardware modifications will increase energy consumption. The antenna array plus the drive circuit will add two watts to each terminal. Energy storage is tight right now, so we can't just add load without restraint."
“Two watts isn’t much,” Susan said, “but we can add an automatic sleep mechanism. When no one is talking, the device will reduce its frequency and go into standby mode, and then wake up when there is a signal.”
"It sounds like slacking off at work," Chen Hao said.
"They're pretty much the same," she replied. "To save electricity, you have to be a little lazy."
Nana added, "The overall power consumption change has been calculated. If only five main station devices are upgraded, the daily increase in power consumption will not exceed one percent, which is acceptable."
Chen Hao looked at the whiteboard, picked up a pen, and drew a line under the original target. "Then it's settled—the first phase: modify the transmitter. Replace the antenna, upgrade the modulation, and establish a 15-kilometer straight-line communication with the target."
He paused, then added, "Let's put mesh networking aside for now, and talk about it when we have more terminals."
Susan looked up: "You thought of that too?"
“Nana just said that there are only five devices right now. What kind of network can we set up? At most, it's like two people making a phone call and having a rope in between them.”
"But we have to lay a solid foundation," she said. "This renovation must include expansion interfaces. We can't just disassemble everything again to add repeaters or connect new nodes in the future."
“Agreed.” Carl closed his notebook. “I will include connection holes in the stand design, and the power supply and data cables will be modular.”
Nana's optical lens flashed twice. "Project file updated. Core technology path confirmed: patch antenna array + qpSK modulation + adaptive power control. Next stage: experimental preparation."
Chen Hao looked around and said, "Let's divide the work. Susan will be in charge of algorithm debugging and code writing, and Nana will assist with model verification; Carl will draw the antenna drawings and find materials to make prototypes; I'll keep an eye on the progress and coordinate whatever is needed."
“I still need the oscilloscope,” Susan said. “I’ll test the signal purity tomorrow.”
“It’s yours,” Carl said. “I’ll avoid your time slots.”
"The printer is mine," Chen Hao said. "I want to print out the task list and stick it on the wall."
Susan rolled her eyes: "You haven't even taken off the stickers you put on last time."
“Those are historical relics,” he said, “inspiring future generations.”
Nana suddenly spoke up: "Reminder, the analysis of abnormal patterns in the current communication logs is not yet complete. We need to extract the common parameters of all disconnection events in the past 72 hours to calibrate the modulation threshold."
“Let’s get started.” Susan sat back in her chair and opened the control panel. “Transfer the data over.”
The screen began scrolling through log entries, with red markers constantly appearing. Nana started a comparison program in the background, with three parallel analysis streams running simultaneously.
Chen Hao walked behind her and glanced at her. "These breaks...are they all on the other side of the slope?"
“Yes.” Susan zoomed in on the map. “Seven interruptions, six of which occurred in the shielded area facing away from the main station. The last one was at the entrance, which was a multipath reflection interference.”
"So, it's not that the signal is weak, but that it's blocked by the mountain?"
“Accurate,” Nana said. “Existing antennas cannot bypass obstacles and lack reflection compensation mechanisms.”
"Then let's make it strong enough to smash through rocks," Chen Hao said. "Anyway, we're not worried about wasting electricity now."
Carl had already laid out his tools on the table and was drawing cutting lines on the metal plate with a pencil. "The patch size is calculated based on a center frequency of 3.2 GHz, and the spacing is 1.8 centimeters," he muttered as he measured. "The substrate thickness cannot exceed 0.5 millimeters, otherwise the VSWR will be exceeded."
"It sounds like making cookies." Chen Hao leaned over to take a look.
“It’s harder than making cookies,” Carl said. “Burning them is just a waste of flour, but soldering them wrong will ruin the whole module.”
"Take your time then." Chen Hao patted him on the shoulder. "I'm not in a hurry. Anyway, no one is going out of the base."
"It's only a matter of time." Susan said without looking up. "The weather data shows that it will be suitable for exploration in three days."
"Who told you I read the weather?" Chen Hao chuckled.
“Just because you don’t look at it doesn’t mean you don’t need to,” she said. “You always have to close the windows in advance when a storm is coming.”
Nana's voice rang out again: "A compatibility issue has been detected with the qpSK demodulation module. If loaded directly onto an existing terminal, it may cause audio output distortion."
How serious is it?
"The voice is identifiable, but it is accompanied by static, similar to a faulty connection on an old-fashioned radio."
“Then it’s better not to say anything,” Chen Hao said. “If you can’t change it, don’t force it.”
“We can add a filter circuit,” Carl said. “A simple two-stage Lc circuit will suffice.”
"You've got work done again," Chen Hao said.
“I’m used to it.” Carl lowered his head and continued drawing.
Time passed slowly. Susan finished typing the last line of code and stretched. A few strands of her hair were messy, and the pen tucked behind her ear almost fell out.
Chen Hao glanced at the clock on the wall; it was almost three in the morning.
"You really don't rest?" he asked.
“Almost,” Susan said. “I ran through the initialization process to confirm that the handshake could be completed.”
Karl looked up: "I'll be there soon too. The blueprints will be ready first thing tomorrow morning."
Nana remained standing, the optical lens flashing continuously. "The first round of signal simulation has been completed. Under ideal conditions, the success rate of communication over a 15-kilometer distance is expected to be 86%."
"Not tall enough," Chen Hao said.
"The actual situation would be even worse."
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