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

The red guillotine fell to the bottom, the mine's backup transceiver connected its antenna, and the 7 MHz indicator light turned from dark red to bright.

Fifteen kilometers to the southeast, the portable radio in Meng Dechang's carriage simultaneously rang with a call bell, and the indicator light on the panel flashed continuously. The long-silent mine finally entered the agreed frequency band.

He put on his headphones, turned up the receiver gain, and the first interrogation telegram pierced through the shortwave noise, requesting confirmation of the coordinates and identification code of the response point.

The mine's transmission power was far greater than that of a portable radio, and the signal spread across the barren rocky beach. The oscilloscopes at the three direction finding points at the base simultaneously lit up with bright lines.

Inside the direction finding vehicle, Lu Qinghe locked the seven-megahertz carrier wave into the DBM-02, and every dot and dart in the earphone was unfolded into a clear rectangular pulse.

"The mine started questioning people, and the message they sent was to confirm the rendezvous point, repeated twice."

Jiang Ming stood beside the power supply cabinet, his left hand in the pocket of his military overcoat, his gaze passing over the antenna and looking towards the dark sand dunes to the southeast.

"Increase the delay by twelve milliseconds, maintain the power at forty percent, and wait for the mine to finish sending its message before touching its interrogation signal."

"What we need to target is the judgment point on the response side."

Lu Qinghe turned the synchronization knob to make the modulator's time base match the rhythm of the mine's reporting code, and the two sets of square waves on the oscilloscope gradually approached each other.

After listening to the first inquiry, Meng Dechang did not send the message immediately. His finger hovered over the key, repeatedly checking the mine call sign.

Switching to 7 MHz after the main channel failed was part of the planned evacuation strategy. However, the technical supervisor should have directly issued a three-digit confirmation code instead of continuously asking for the rendezvous coordinates.

The driver leaned half his body into the car.

"Director, have they replied?"

"Shut up, go look at the road to the east."

Meng Dechang narrowed the receiving bandwidth and checked whether there was any induced noise in the signal. The mine carrier wave was stable, and the code reporting method was consistent with the agreed personnel.

He still felt something was wrong.

The mine has already obtained the evacuation map, and there is only one possibility for requesting a re-report of coordinates: the original record is damaged, or the on-duty personnel need to confirm that they are still in control of the other end of the radio.

If no response is received, the technical supervisor will not leave the underground passage with the core data, and the truck and spare documents will become useless.

The encirclement forces are tightening their grip from both sides, leaving neither side with enough time to reassess the situation.

Meng Dechang turned the portable radio power to the first level and entered the coordinates of the receiving point and the check code.

The low-power carrier wave left the barren rocky beach, and the No. 3 radar base was the first to acquire the azimuth, but the signal was close to the noise floor, and the cross lines were still oscillating within a range of several hundred meters.

The mine receiver heard the reply; the first two digits passed clearly. As soon as the first dot of the third digit entered the decision circuit, a narrow pulse was injected from the side of the main antenna.

The relay emitted a continuous buzzing sound, and only a truncated line segment remained on the decoding paper tape, preventing the verification code from closing.

"Received the beginning of the coordinates, but the second half was cut off by the pulse."

The operator lowered the gain, trying to find the missing part from the noise.

The technical supervisor examined the paper tape; the first two numbers corresponded to the southeast direction, but the error covered several kilometers, making it impossible to confirm the specific weathered rock zone.

"Request increased power and retransmission of complete coordinates."

The second inquiry telegram was sent from the mine, faster than the first, and contained only the requests to increase transmission speed and repeat the message.

After listening to the decoding, Lu Qinghe's palm remained on the synchronization knob.

"The mine has taken the bait; it's demanding that the barren wasteland increase its power."

"The source thunder has been reduced to 30%. Next time, we will only hit the middle of the checksum so that both the preceding and following content can be heard."

Fang Xudong stood next to the field strength meter and looked up at Jiang Ming after hearing the parameter.

Completely blocking the signal would lead Meng Dechang to conclude that there was a circuit malfunction, while allowing the coordinates to pass through would cause the mine to immediately terminate communication. Only by allowing both sides to continuously hear most of the content could the transmitting end be forced to actively increase the brightness.

The pulse cuts a narrow segment in the code, leaving a gap just enough to arouse suspicion in the mine, but not enough to make both sides abandon communication.

This network does not rely on higher power; it tightens by using reception thresholds, personnel selection, and evacuation time limits.

Inside the train carriage on the barren rocky beach, Meng Dechang heard the request to increase the launch speed and his gaze fell on the power knob.

The first level is sufficient to cover 15 kilometers. Continuing to push it up will increase the ground wave field strength several times, allowing the base direction finding station to reduce the azimuth error in a shorter time.

He pressed the transmit button, only re-reported the checksum, and kept the power at the first level.

Yuanlei-1 inserted pulses according to the timing set by Jiang Ming. The mine received the first and last segments of the check code, but the middle three digits were missing again.

The technical supervisor picked up the microphone and switched to using a manual key to repeat the requirements.

"The other side is testing us. They're issuing an ultimatum: if we don't increase the power, the backup will be canceled."

The operator typed a short message, ending with a countdown to the evacuation of the mine personnel, with the seven-megahertz carrier wave lasting for more than twenty seconds.

The three direction finding stations used this method to complete the mine's benchmark calibration, then turned all the antennas back to the southeast and waited for a response from the other end.

After reading the ultimatum, Meng Dechang moved his hand from the key to the power switch, nearly shutting down the entire radio station.

The driver returned from outside the car, bringing news that there were no vehicles on the eastern highway, but the distant gunshots could already be carried by the wind to the barren rocky beach.

If anyone in the mine is captured, the Lightning-7 data, records of equipment allocation over the years, and the source of the technology will all fall into the hands of the classified system.

He can abandon the operators, but he cannot abandon the technical supervisor who has mastered the entire design process.

Meng Dechang pushed the power knob to the second position, and the anode current of the portable radio increased rapidly, causing the car battery to emit a heavy electrical sound.

"The last time."

He re-entered the coordinates and, starting with the identification code, sent the location of the barren rock beach, the weathered rock number, and the response time item by item.

The high-power shortwave radar left the rocky area, the direction finder of the No. 3 radar base crossed the centerline, and the No. 4 outpost and the base mound also received clear carrier waves at the same time.

"Target power increased sixfold, azimuth 147.3 degrees."

Lu Qinghe used his left hand to record the location of the mound, and his right hand to input the cross angle transmitted from the No. 4 outpost into the transparent coordinate board.

Comrade Song covered the direction finding lines of the No. 3 radar base with the radar. The wide triangle originally formed by the three thin lines quickly shrank and finally converged on a narrow rock trough on the north side of the barren rock beach.

"The nighttime ground wave correction is -0.6 degrees, and the ionospheric reflection component has been eliminated."

Fang Xudong used a data ruler to check the three baselines. The angle between the mound and the No. 4 outpost was large enough, and the remaining error came from the map scale and the reflection of the weathered rocks.

Jiang Ming continued to look at the distant sand dunes, his hand remaining in his coat pocket.

"Have Meng Dechang repeat the timing again, but only cut off the last two check digits of the pulse."

Lu Qinghe adjusted the delay. After receiving the complete coordinates, the mine still lacked verification and had to issue a brief confirmation request.

Meng Dechang had already increased the power, and could not temporarily back down during the transmission process. He could only repeat the last set of time codes as agreed.

The second carrier wave lasted for twelve seconds, and the three direction finding lines overlapped again. The deviation caused by the reflection from the rock wall was also canceled out by the phase changes of the two sets of phase changes.

Lu Qinghe moved the cross lines on the transparent plate so that the center pressed against the third weathered rock trough on the northern edge of the barren rock beach.

"Coordinates locked. East longitude is 374.6 according to military map number, north 219.3, error 10 meters."

She copied the coordinates onto a telegram and handed it to Comrade Song to deliver to the command post.

Fang Xudong held the data ruler and stood in front of the three-dimensional pressing sketch for a long time without moving.

Thirty-eight minutes ago, they couldn't even calculate the next jump of the mine's backup local oscillator, and the encircling forces also lost their communication coordinates.

Jiang Ming dismantled the irrational number mirror image, used the frequency hopping gap to reconnect the troops, and drove the mine and Meng Dechang into the same seven-megahertz narrow gap.

The frequency domain blackout that had originally trapped everyone has, after several parameter adjustments, become an electromagnetic fishing net without any gaps.

The propagation models, cryptography textbooks, and measurement methods that Fang Xudong relied on in the past had not failed, but when this knowledge came into Jiang Ming's hands, it was directly turned into tactical tools that forced the enemy to choose.

"Coordinates confirmed."

After receiving the telegram, Director Wang circled the location of the barren rocky beach with a red pencil, then grabbed the Type 54 pistol from the table, checked the magazine, and put it back into the holster on his waist.

"The guards will follow me. The two jeeps will turn off their headlights and circle around to the north side of the weathered rock from the east side of the road."

"Notify nearby patrol teams to block off the south entrance. The target is carrying a radio and may be armed; he must be captured alive."

The engines started up one after another outside the command post, and the jeep drove out of the base along the leeward slope, its wheels rolling over the frozen sand, without turning on a single light.

Outside the mine, the First Battalion crossed the No. 2 fork from the North Gully, while the Second Battalion advanced eastward along the western rock wall. The two teams gradually tightened the network based on the restored coordinate network.

At the other end of the seven MHz band, the technical supervisor tore off the code paper, stuffed it into a metal tube along with the core data, and led two operators into the old laboratory two hundred meters underground.

The lead door, which had been closed for many years, slammed shut behind him. He walked to the wall and turned off the guillotine switch with its independent power supply.

A dark red glow appeared deep inside the lead box, followed by a deep hum that spread along the underground pipes.