[ECHO ARCHIVE · LAYER 0 · CARRIER · 0% DECODED · KEY: — · REGISTRAR: LIN WANQIU]
Night shift starts at midnight. At handover the day man told me the K band had picked up two suspicious samples that afternoon and asked me to "give them a quick look." A quick look meant his shift was over. His name was Xiao Gao. He had a habit of talking every problem down a size; in his mouth, problems went on a diet—suspicious samples, slight drift, quick look. He wasn't a bad sort. He just believed the world held no big things.
The night room sits beside the machine hall, twenty degrees all year, winter and summer alike. I took over from him and made my usual round of the hall first. Machine Three's water cooling had been replaced once; the label gave the date, in Adebayo's handwriting, crooked. In the fridge sat a yogurt somebody had left and nobody claimed, four days expired, still there. I signed the inspection sheet, steeped a bowl of instant noodles, and only then went to the terminal. Night work is mostly waiting, and the waiting can't be cut; cut it and it isn't a shift anymore, it's a tour.
The institute's automatic classifier had already looked, and its verdict was crisp: local RF leakage, recommend closing the ticket. The machine doesn't stay up nights. It goes by the book—narrowband, continuous, no Doppler. Those three together meant, on its ledger, a neighbor's device leaking current. It had opened files on more than four thousand of these. It tires before people do.
I fed the samples back through with "local" taken out of the weights and had it classify again against a celestial source. It thought for half a second and said: known satellite, low confidence. Wrong again. It only held so many cards, and it had played them. By procedure I should have entered "agree" in the close-out field and gone to my noodles. Instead I cut thirty seconds of raw data, meaning to take one look myself before signing. That isn't dedication. That's a practiced hand—people on nights keep a few small rituals of their own, and until I've had my look, the signature never sits solid.
Interference that keeps a schedule I had handled before. Three years back there was one that arrived every morning at three exactly: a spike pulse, forty minutes long, regular as a heartbeat. The whole institute spent a week hunting it, and in the end it was me, driving the mountain road, who ran it to ground—a fish farm below the hill, an aerator pump, the timer set to three, the owner dodging peak-rate hours. I still remember the close-out wording: aquaculture, friendly negotiation, resolved. The owner tried to press a bag of crucian carp on me; I wouldn't take it, and later he sent the fish around to the canteen. The crucian soup that day was good. I've been through dozens of these—dawn cases, punctual cases, narrowband cases—each with its own story, and every story sat on the ground.
So I gave myself half an hour. If the thing showed any flaw that put it on the ground inside the half hour, I'd handle it the old way.
The noodles sat at the corner of the desk. I didn't touch my chopsticks.
I narrowed the bandwidth to two hundred hertz and re-integrated.
The signal rode the second harmonic of the hydrogen line, narrow past all reason. Not a figure of speech—an instrument reading: a little over three hertz. In this trade, anything wider gets called a band. Three hertz can only be called a line. Local leakage is never this narrow. A microwave oven leaks as a wide-spectrum glitch; a cheap power supply makes comb teeth. I have seen the spectrograms of every kind of RF interference on Earth, and none of them gathers its energy inside three hertz and then sits still.
I checked whether it drifted. Local interference sways with temperature and wind; you can see it in the frequency. This one didn't sway. Ten minutes, and the frequency marker never moved—steadier than the rubidium clock in our own machine hall. That one I kept out of every report. Writing it down would have felt like insulting our own.
My first suspect was us. That's the rule: blame yourself before you blame the sky. I went down the receive chain piece by piece—was the downconverter's local oscillator holding lock, was the feed at temperature, was the digitizer's clock clean. One connector had a record; it had worked loose once last year, and I reached over and gave it a half turn. While I turned it I was hoping the signal would die. If it did, everything was easy: sleep, and write "connector, fixed" on the handover sheet in the morning. The signal stayed. Three hertz, not moving. I archived the chain self-test screenshots, eleven pages in all.
Then I pulled the pointing data—the second move, and one you don't skip. The antenna's pointing record laid out frame by frame, and the strongest direction was unmistakable: Cassiopeia, elevation forty-one degrees, tracking the celestial sphere and not letting go for one second before it set. Interference doesn't follow the sphere. Interference grows out of the ground.
I sat there. The noodles had gone stone cold; I pushed them aside.
The institute at night has a specific kind of quiet: the fans of the main racks make the bass line, and the chiller, starting and stopping every twenty minutes, makes the punctuation. I had worked inside these sounds for years and could tell the time with my eyes shut—after the chiller's third start, four o'clock was near. Now and then a car came over the mountain road, the sound climbing until it died halfway up. That is how the mountains are: sound has more patience than people. That night I counted chillers and saved the power curve in three copies—one local, one to the backup machine, and one into the pool where the inspection archives are kept. No procedure asks for a third copy. I only felt that a thing like this, with one witness tonight, wasn't right.
One more thing on the desk, sounding all the while: the Red Lantern radio, a 1987, left to me by my father. It cost him three months' salary that year, and the first thing he did at home was copy a full page of band frequencies into a notebook; the notebook still rides in the radio's leather case, paper yellowed, writing sharp. The radio lives beside the oscilloscope. On nights I keep it switched on, shortwave band, hissing. Nobody at the institute minds—the night room is a kind of junk shop; one man keeps a camp cot in it, another a crate of oranges. Adebayo calls it the Old Comrade.
It needs warming up before the sound settles. The year before last I opened the back panel to change a wire, and inside was a solder joint my father had repaired himself—solder piled thick, rough work, but in a dozen years it had never failed. The wire I changed, I soldered with the old roll from his drawer. He taught me how to listen to shortwave: ten minutes of static first. Don't hunt for anything. Let your ears get good and dirty, then go looking—only then do you hear what's there. The ear, he said, is like a wok; it has to heat empty first. At ten years old, I found the speech long-winded. Now I follow it step for step, and have for over ten years.
Inside the static I finished what needed finishing: logged the frequency, saved the raw samples, gave the day's duty log its title. I thought about the title and wrote: K-band unknown narrowband, pending review. At the close-out field I entered neither "agree" nor "veto." I pushed the whole ticket back into the queue and let it spend the night.
At five past three, with nothing left to do, I watched the clock. It's one of the night shift's bad habits: once a thing turns strange, you start keeping watch on it. The curve lay flat on the screen; the seconds went around. At ten past three I put my hands on the keyboard and didn't type. At eleven past I watched the curve take a step.
The power jumped one notch.
Not more, not less—like climbing a stair. Then flat again, holding flat. I waited until twenty to four; no second step came. I zoomed the time of the jump down to the second: 03:11:44. Then I pulled the inspection archives from the days before and went through the whole week. Thursday before dawn: 03:11:44, the same notch. Wednesday before dawn: 03:11:44, one notch. Beyond that, nothing—the archive rolls, seven days only.
It came every day and grew a notch a day. We just hadn't seen it until today.
By the old rules, a thing like this gets a temporary designation so the ledger can call it by name. The discoverer assigns it: two letters from the discoverer's surname, then month and serial. I typed LIN-0307, then felt it was wrong. It had existed before me—at least three days before—and the number read as if I had given birth to it. I deleted it and left the field empty, so the ledger wouldn't rush to claim it either. Fields left empty are rare in this institute's whole history.
I messaged the duty chief with the frequency and the bearing, so it would be the first thing he looked at when he came in. He usually arrives at seven thirty. After sending it I stopped watching the screen and picked up my phone. A missed call from my mother, ten the night before; I hadn't taken it. And a voice message from Lin Nian, forty seconds: "Mama, I played for Grandpa's radio today. I got two notes wrong. Teacher says two wrong or fewer and you pass Grade Three. When are you coming home? I'll play it for you."
I played it once and didn't reply. Not that there was nothing to say—there are things you can't say at four in the morning. I laid the phone face down on the desk.
The duty chief came at seven twenty-six, four minutes early; my message, probably. His name was Tong. He reads things slowly, and before he reads anything he pours a glass of water. He sat in my chair and spent ten minutes on the three days of stair-steps without drinking a drop. Then he asked: "You checked the chain yourself?" "Eleven pages." "And the classifier?" "It said microwave oven." For once he didn't smile. He asked: "Your opinion?" I said: "It isn't local. The bearing tracks the celestial sphere, and the frequency stability beats our clock. Either it's very far up, or very close down—close enough to be inside our feed. I tested the feed overnight; temperature normal." He nodded, wrote two lines on a sticky note, folded it into his shirt pocket. His habit: important things don't go into the computer, they go into a pocket. "Don't report yet. Watch it three days. You keep your nights; days, I'll put Lao Song on the recheck—he chatters, but his hands are steady, and he reads the ledger, not the conclusions. If it still looks like this after three days, report up." I said okay. Standing to leave, he added: "Those noodles from yesterday still sitting there?" I said yes; they'd gone cold. "Cold, then throw them out."
I got off at eight thirty, the sun high and warm. A vegetable truck crawled along the mountain road; I stayed behind it and didn't pass. The apartment was empty—my mother had taken Nian to school. An upturned bowl on the table, a note under it in her hand: Soup is in the pot. I heated the soup and drank it. On the balcony stood several unopened boxes, all my father's things, untouched in the two years since my mother moved in. The top box was marked "tapes," its sides wound twice with tape, wound hard—her way of doing things. I didn't open it. I pushed the box into the corner, squared it against the wall, went back inside, and slept until four in the afternoon. My dream was all straight lines, level and plumb, one lying across another—like a ledger, or like a music staff. When I woke, the curtains glowed and a scrap collector's loudspeaker downstairs was looping one sentence, over and over. I lay there a few minutes and went through the night in my head: the frequency remembered right, the bearing remembered right, 03:11:44 remembered right. The good thing about numbers is that after a night's sleep they are still standing where you left them. But the first thing I thought of when I woke wasn't the signal. It was a word in Nian's voice message: passed—two wrong notes or fewer, and you pass Grade Three. She had played for Grandpa's radio. That radio was in my office at that moment, not at home. Most likely she had played to the old photograph instead—my father's picture on the piano, the lid always open a crack. Or she had remembered it wrong. A seven-year-old doesn't keep these things by accuracy. She keeps them by giving.
When it got dark I went back for my shift. The Red Lantern was in its third minute of warm-up, the sound steady, shortwave still hissing. I waited out the full ten minutes—ears dirtied enough first—then pulled the raw data up again. After the power step, the modulation had carried on; the bitstream didn't say one word extra for being watched. I cut sixty thousand symbols, ran folding and alignment, and read the sync by eye. An old craft. The machine can do it, but sometimes the eye recognizes it first. The eye knows things by rhythm: music you know cold, you hear which note came in half a beat late without counting. I counted the interval: a cycle of one hundred eighty-eight bytes, the frame sync word at the very head, the pattern exact. I counted again. After the second count I stood up and went out to the corridor for a while, came back, and counted a third time. All three the same.
One hundred eighty-eight bytes. I knew that number. I knew its fittings, I knew its error correction—had seen it, had repaired it. In school we built a complete link on that standard in the lab, from the signal entering the room to a picture coming out; it took a semester.
I knew this thing. Every satellite TV system on Earth is running it. A signal out of the direction of Cassiopeia, in transit nobody knows how many years, lands in our antenna carrying the error-correction code our own television has used for thirty years.
To make sure it wasn't my eyes, I pulled a control: a downlink stream from a satellite in orbit, run through the same folding and alignment. Two sync diagrams side by side—one from a bird at thirty-six thousand kilometers, one from somewhere unknowable in the direction of Cassiopeia. Frame head against frame head, cycle against cycle, the overlap clean through, like two sets of homework copied from the same sheet.
I opened a new page of the duty log. Title: K-band unknown narrowband, second night. For the remarks column I thought a long time and wrote one line—
Channel coding: the human satellite TV error-correction standard.