I started with a ship full of max-level veterans, and I'm just a complete noob.

Jiang Ming stared at the reading of 0.87 for more than ten seconds, but did not rush to a conclusion. Instead, he took out the assembly record book of five sample tubes of type B tube from the bottom drawer of the test rack and turned to page 02.

The batch number column for the tungsten filament reads: CW-K47/Su.

The batch number of the tungsten wire for the other four is: TW-301/National.

He took the notebook under the light to examine it closely. Old Sun had marked a line of small characters in pencil next to the batch number: "Last section of the iron box in the southwest corner of the waste warehouse, about 42 centimeters."

Soviet-made fine-grained tungsten wire.

Jiang Ming closed the notebook and turned to look at Lao Sun, who was tidying up his tools.

"Was the filament in the 02 lamp made of Soviet filament?"

Old Sun looked up from his toolbox, a screwdriver in his hand. He thought for a moment before answering, "Yes, I searched the warehouse for ages before finding that piece. Its purity is half a grade higher than the domestic ones, and the grains are finer. I thought it would be safer to use it on the 02."

What does high purity mean?

"The evaporation rate is low," Old Sun replied quickly.

Jiang Ming nodded and turned the notebook back to the test data page.

Soviet silk has high purity, a lower evaporation rate, smaller cross-sectional changes, and smaller resistance increments over the same operating time.

Therefore, the high amperage of 0.87 amperes is unlikely to be due to filament degradation; the greater suspicion lies in another component.

He bent down and pulled out a standard resistance box from the bottom of the drawer.

The paint on that old decimal knob box was worn, but the precision wire-wound resistor inside was still reliable.

"Xiao Zhao, disconnect the filament circuit of the zero-two lamp and connect the ammeter in series with the standard box."

Xiao Zhao responded and, following Jiang Ming's instructions, disconnected the filament power supply jumper, connected the standard resistance box to the ammeter measurement circuit, and then rotated it to the known resistance value.

Jiang Ming stared at the dial reading, wrote down the measured value on a piece of paper with a pencil, and subtracted it from the nominal value of the standard box.

The difference is 0.015 amperes.

After the instrument had been working continuously for more than 200 hours, the internal manganese-copper wire shunt accumulated temperature, causing the zero point to drift by 0.015 amperes.

After deducting this drift, the actual current change of the ethylene 0.2 filament is only 0.005 amperes, which translates to a resistance change of less than three-thousandths, perfectly normal within the tungsten filament's 600-hour design lifespan.

Jiang Ming removed the standard box, restored the filament power supply, and wrote a line in the logbook: 266h, zero-two filament ammeter drift 0.015A, calibrated, tube body normal.

He stopped writing on the paper and added: "From now on, all five ammeters will be calibrated with the standard box every 24 hours."

"Little Zhao."

"exist."

"From now on, every morning at eight o'clock, all five watches will be calibrated in turn, and the data will be recorded on the back of this page."

Xiao Zhao took the notebook, glanced at it for a few seconds, nodded, and stuffed it into his workstation drawer.

Jiang Ming straightened up and glanced at the five ammeters.

01 284, 02 284, 03 281, 04 284, 05 284.

The timing relay of the pulse generator clicks every minute on the test fixtures 04 and 05, injecting reverse pulses on time, pushing the impurities in the two tubes back into the depths of the grain boundary.

The entire testing chain is currently stable.

He glanced at the old watch on his wrist.

10:40 AM.

Only twenty minutes have passed since the problem with the filament was discovered in the early morning, but those twenty minutes reminded him of one thing: the 500-hour test is not only on the tube, but also on every meter, every wire, and every connector that revolves around the tube.

The creases on the telegram in the breast pocket of my work clothes had softened from my body heat.

The frontline staff said there was no need to interrupt their work; the delayed lines, along with A02 and A03, could still hold out.

How long it can last is a question, but that's not something he can control right now.

What he can do is make the type B tubes run for 500 hours to pave the way for mass delivery.

……

Northwest Base Communications Command Post.

At four o'clock in the afternoon, the sunlight over the Gobi Desert began to slant, and the sandstorm dragged a layer of yellowish-brown mist on the horizon.

Old Zhou pushed open the door of the wooden house and walked in, clutching a folded piece of paper in his hand, his steps quickening considerably.

Chen Zhiyuan was touching up the white paint markings on the delay line sub-capacitor knob when he heard the door open. He looked up, saw the expression on Lao Zhou's face, and stopped writing with his brush.

"The order has been issued."

Old Zhou unfolded the paper and laid it out on the table.

An oval red stamp was affixed to the top of the paper; Chen Zhiyuan recognized it as the seal of the military region's operations department.

Lu Qinghe turned around from beside the receiver, her gaze falling on the first line of the paper.

Operation Iron Chains.

Old Zhou pointed to the text with his index finger as he scrolled down, reading aloud as he pointed: "Given that the enemy's position has been confirmed, the encirclement operation will be launched at midnight tonight. The First Company of the Guard Battalion will approach from the southeast along the dry riverbed, while the Second Company will flank from the west via the low sand dunes. The six-man action team from the Security Department will accompany the First Company to be responsible for the capture."

His finger stopped at the next section.

"Each direction finding point must maintain continuous monitoring of the target signal and provide azimuth guidance throughout the entire operation. Any change in azimuth must be reported to the command post within thirty seconds. During the operation, receiving equipment must not be turned off, and core components must not be replaced, resulting in a monitoring interruption of more than two minutes."

Lu Qinghe shifted her gaze from the paper to the A02 in the cabinet behind her.

The anode cap of the tube gleamed with a gray metallic sheen in the dim light of the cabinet, while the faint red glow of the filament shone through the ventilation holes.

The transmission current recorded at noon today was 152 microamps, which is 6 microamps lower than at the same time yesterday.

If the operation begins at midnight and lasts for six hours until dawn, based on the current rate of decay, the Jia-02 is likely to fall below the usable threshold of 120 microamps during the operation.

"Has the filament of the Jialingsan lamp been preheated?" she asked Chen Zhiyuan.

"Available anytime."

Chen Zhiyuan put down his brush, walked to the spare tube shockproof box, and patted the lid.

"But the drawing specifies a time limit of twenty minutes, and the switching itself cannot exceed two minutes. After connecting, it can only be used for a maximum of twenty minutes before it has to be disconnected."

Lu Qinghe did not reply.

She looked at the words "No interruption for more than two minutes" on the order paper again, then took out the operation record card of Class A03 from the drawer, circled the twenty-minute time limit with a red pencil, and pasted it on the upper right corner of the receiver panel.

Old Zhou stood in front of the map, picked up the red and blue pencil, and began to mark the encirclement route on the military map.

To the southeast, a red arrow curves and extends along the dry riverbed.

To the west, a blue arrow crosses the sand dunes and then converges eastward.

The point where the two arrows converge is precisely the 800-meter ellipse circled in red pencil.

His pen paused on the small square mark next to the oval, then he turned to look at Lu Qinghe.

"The survey team's records say that the entrance to that old bunker faces southwest and is three to four meters deep. No one has ever gone inside to see what's going on."

Lu Qinghe walked over and stared at the contour lines next to the box.

"If the person is underground, even if the encircling force reaches the surface, they may not be able to capture them directly."

"Does the company commander know about this?" Chen Zhiyuan peeked out from beside the shockproof box.

"It was mentioned in the briefing."

Old Zhou tapped the edge of the map with his pen.

"The operations department suggested that engineers cooperate, but the order did not specify whether the engineers had been incorporated into the operation sequence."

None of the three spoke again.

The only sounds in the wooden house were the low-frequency hum of the vacuum tube filament in the receiver and the faint sound of the oscilloscope scan lines tracing across the screen.

Lu Qinghe sat down in front of the receiver, set the alarm clock to 11:45 p.m., leaving 15 minutes for a final equipment status check.

In the distance, the oscilloscope baseline was as smooth as during the day, with occasional spikes or jumps in thermal noise.

At 5 p.m. sharp, the enemy radio station sent a sequence of three short, one long, and three short messages.

The delay line suppresses the residual pulse to below 8%, and the azimuth line does not shift.

5:15, second group.

5:30, third group.

The interval remains fifteen seconds.

Business as usual.

Until sunset.

The Gobi Desert twilight is extremely short; the sun dips below the horizon, and the sky changes from orange-red to iron gray in just a few minutes.

As Lu Qinghe was recording the last set of routine azimuth data in the evening, a waveform suddenly appeared on the oscilloscope screen.

It is not a pulse.

It was a continuous carrier wave with a frequency 1.2 kHz higher than the usual transmission signal, which lasted for a full eight seconds before being interrupted.

Her finger hovered over the recording pen, her eyes fixed on the lingering glow of the now-vanished bright line on the oscilloscope screen.

Eight-second continuous carrier wave, without modulation keying, without interruption.

It is neither "three shorts, one long, and three shorts" nor any pattern that has appeared before.

It was like a pipe being forcibly opened, and something was poured in all at once.