The spectrum analyzer was no stranger to them. They came in large and small sizes – the large ones as big and heavy as old oscilloscopes in university physics labs, the small ones as portable and light as Nintendo handhelds. The analyzer’s purpose was to detect radio waves, precisely capturing invisible electromagnetic waves in the air and displaying them through an oscilloscope.

If there were waves at 14MHz, there would be a peak at the 14MHz position on the horizontal axis.

If there were waves at 144MHz, there would be a peak at the 144MHz position on the horizontal axis.

However many waves, that many peaks – double waves meant double peaks, and big waves meant high peaks.

Soon the Radio Commission’s person brought the spectrum analyzer. Someone knocked “dong dong” at the door, and Wang Ning hurried to open it. Standing outside was a young man with messy hair, dripping with sweat, wearing a blue short-sleeved shirt and black shorts. This was the unfortunate soul called by his inconsiderate leader to help late at night, carrying the spectrum analyzer wrapped in cables.

Indeed a workplace newcomer who’d just graduated, not yet knowing how to refuse work that wasn’t his responsibility.

If he had Old Bai’s thick skin, he should have answered the phone with “Ah, Brother Wang, sorry, I’m busy… ah… ah…”

While adding heavy breathing sounds.

Even the most inconsiderate leader would know to back off at that point.

Old Wang might even show concern for the young man’s health, warning him not to get too caught up in such activities.

“Brother Wang, I brought the spectrum analyzer,” the young man panted, exhausted from carrying such a large device up eight floors. “Is this the one?”

“Ah, thank you, thank you! Yes, yes, this is it. Little Zhu, you’ve been such a great help,” Wang Ning quickly took the analyzer. “You must be tired? Sit down and have some water.”

“No, no, thank you, Brother Wang,” Little Zhu waved his hand. “If there’s nothing else, I’ll head back now. See you, Brother Wang.”

“See you tomorrow!”

The young man darted downstairs in a flash.

Wang Ning placed the white spectrum analyzer on the dining table in the living room. This thing was even bigger than the Icom 725 shortwave radio in the room, with a white engineering plastic case and built-in handle. Its control panel had an LCD screen on the left half and neat rows of English letters and number buttons on the right.

“What’s this thing?” Mom came out from the kitchen, casually untying her apron. “You brought another radio?”

“Spectrum analyzer,” Wang Ning answered. “Agilent costs several tens of thousands of yuan each.”

“From the Radio Commission?” Mom asked. “You know how to use this thing?”

“I’m an expert,” Wang Ning patted his chest. “You know when I first used a spectrum analyzer? The first time I operated this thing was…”

“When was it?” Zhao Bowen asked.

“Twenty years ago,” Wang Ning said.

“So you’re very experienced,” Zhao Bowen said. “Director Wang.”

“Indeed! Back then we were using old HP spectrum analyzers, helping China Unicom adjust pager towers,” Wang Ning said. “Testing the phase difference between two antennas on the pager towers. You know that stuff? Because there was a phase difference between two antennas that needed to be unified, we had to use this thing to measure. That was still in the beeper era.”

“When was the last time you used a spectrum analyzer?” Dad asked.

“The last time was the first time.”

“Are you really from the Radio Commission? Haven’t touched a spectrum analyzer in twenty years?” Dad asked. “Why does the Radio Commission have useless people like you? Why is the country feeding parasites like you?”

“Get lost! I just said I haven’t operated it personally, but can’t I direct others to operate it?” Wang Ning said. “Aren’t old folks allowed to slack off a bit?”

He plugged in the analyzer’s power supply and turned it on. The LCD screen lit up.

The spectrum analyzer was more convenient to use than the radio station – importantly, it wasn’t picky about the power supply, working directly with 220V household AC power.

Unlike radio stations that only used DC power, which meant radio enthusiasts had to keep car batteries at home.

The screen showed a grid coordinate system, with signal frequency on the X-axis and radiation intensity on the Y-axis. An uneven yellow sawtooth line jumped around on the coordinate system. The jumping line indicated background noise – the static you hear when radios can’t pick up signals, the snow on TVs without signals. It could come from humans, nature, or even cosmic microwave background radiation. Besides the sawtooth-like background noise, there were several obvious protruding wave peaks.

These peaks were signals captured by the spectrum analyzer – they could be broadcasts, walkie-talkies, or other radio stations. In modern society, radio waves are everywhere, and pervasive, and the analyzer’s scanning capability could theoretically detect all frequency electromagnetic waves nearby.

Wang Ning began setting the analyzer’s basic parameters.

He pressed the “AMPLITUDE” key on the right side of the control panel – this word meant the signal and radiation intensity, setting the Y-axis parameters.

Wang Ning set the Y-axis unit to dBμV.

Next came the X-axis parameters – the analyzer monitored all frequency bands and would pick up lots of unwanted messy signals. Wang Ning needed to monitor Bai Yang’s Icom 725. Bai Yang’s frequency was 14 megahertz, so Wang Ning needed to narrow the monitoring range.

He pressed the “FREQUENCY CHANNEL” key in the upper left of the button area. This allowed setting X-axis parameters, namely the analyzer’s frequency monitoring range.

“Little Yang!” Wang Ning asked, “It’s 14 megahertz, right?”

“Right!”

Wang Ning narrowed the analyzer’s monitoring range to 5-50 megahertz.

“Little Yang! Press the PTT and try it!”

Bai Yang pressed the hand mic at this prompt.

The Icom 725 transmitter sent out a signal.

Since Bai Yang didn’t speak, the station transmitted an unmodulated carrier wave – just a meaningless electromagnetic radiation.

Immediately, the waveform on the analyzer’s display in the living room quickly climbed, forming a small peak right at the 14 megahertz position – undoubtedly Bai Yang’s radio signal.

“Look, this is Little Yang’s signal,” Wang Ning pointed at the peak on the screen. “Though it’s a bit weak, it’s very clear, around 14.255 megahertz. Later we’ll do this – when Little Yang connects with that BG4MSR, we’ll try to catch their signal. If we can catch it, that’s good – we have ways to find the signal source.”

“What if we can’t catch it?” Bai Zhen asked. “You couldn’t hear that girl’s voice when you monitored before, right?”

Wang Ning pondered for a while.

“It’s unlikely we can’t catch it. If the IC-725 can receive the signal, there’s no reason we can’t. But if – I’m saying if we can’t receive it-“

“What would that mean?” Bai Zhen asked.

“It would mean the spectrum analyzer is broken,” Wang Ning said. “We’ll just have Little Zhu bring another analyzer.”

“What if we still can’t receive it with another analyzer?”

“Then we’ll have Little Zhu bring yet another one,” Wang Ning said.

“What if we can’t receive it with any analyzer?”

“Then we’ll get another Little Zhu.”