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

"Eight decibels cannot simply disappear into thin air."

Fleischer stood in front of the blackboard, his cuffs still stained with white powder. After taking the field strength record from Jiang Ming, he first crossed out half of the free space loss formula.

The blackboard quickly displayed cross-sectional views of the mounds, sand dunes, and mine shafts, with the heights and distances of the three locations marked on the coordinate axes.

"Your calculations assume that the near-surface refractive index varies according to the standard gradient. However, the low-altitude meteorological records from the command post that you also sent show that the surface temperature is -14 degrees Celsius, but at an altitude of 100 meters, it is close to -3 degrees Celsius."

"The sandstorm has just ended, and the upper-level thermosphere has not yet dissipated."

"Then let's stop using the flat propagation model."

Fleischer held the chalk horizontally and drew a curve above the mound, first diagonally upward into the warm layer, then gradually curving downward, crossing two sand ridges, and then falling towards the mine shaft.

"When cold air is close to the ground and warm air is above it, the temperature gradient reverses, and the refractive index decreases faster with altitude. When the gradient is large enough, the near-surface layer will enter a super-refractive state, and the beam will gradually bend downwards along this gradient."

Jiang Ming stared at the arc.

"The first beam can be launched close to the ground, and theoretically the upper edge of the main lobe should also cut into the inversion layer."

"The angle of incidence is too small. The lower edge of the main lobe hits the sand beam first, and the upper edge penetrates the thermosphere. The energy that actually bends back along the superrefractive layer only accounts for a portion of the energy of the side lobe."

Fleischer added several scattering lines below the first curve, and after two diffractions, only faint chalk marks remained at the endpoint.

"Dust particles are much smaller than wavelength, so even at high concentrations, they are not enough to eliminate eight decibels on their own. They do increase scattering slightly, but more importantly, they help mark out near-surface airflow and stratification boundaries."

"Therefore, the main loss of eight decibels still comes from diffraction of sand dunes and reflection from the ground."

"There's also destructive interference. The inversion layer itself isn't the source of that 8 dB loss; it changes the propagation path. Your ground-reflected wave and the direct wave are almost half a cycle out of phase at the mine antenna opening, and most of the energy is lost here."

Another set of calculations appeared on the blackboard: refractive index gradient, inversion layer height, ground reflection coefficient, and beam curvature, all incorporated into the same propagation path.

Jiang Ming added the wind speed and temperature difference measured by Lu Qinghe, and finally obtained the lower boundary height of the inversion layer as 67 meters.

"What elevation angle is needed to insert the main lobe into this layer?"

Instead of calling out the numbers, Fleischer handed over the chalk.

"You have the antenna aperture, main lobe width, and the distance between the two sand dunes. Calculate it yourself."

Jiang Ming listed the half-power beamwidth of the Yagi antenna on the right side of the blackboard. Using the lower boundary of the inversion layer and the two sand beams as constraints, he successively substituted the refractive index gradient to deduce the rise angle of the main lobe center.

The first result was 7.4 degrees. After substituting the height of the second sand dune and the elevation of the mine receiving antenna, the center of the downward-bending main lobe was 16 meters higher than the receiving port surface.

He corrected for the boundary tilt caused by the wind speed and recalculated.

Seven o'clock two degrees.

The main lobe of the beam will cut into the superrefractive layer before the first sand beam, bend downwards along the refractive index gradient, and fall to the upper edge of the mine receiving antenna after passing the second sand beam.

"After raising the entire antenna, will the stress on the support structure alter the feed matching, causing the reflected power to burn back into the magnetron?"

"The VSWR depends on the feed and load matching, not on the antenna orientation. As long as the support remains rigid and the feed point and element spacing remain unchanged, a 7.2-degree elevation will not cause the reflected power to run away."

Fleischer circled the two propagation paths on the blackboard together.

"You always like to treat the atmosphere as a blank space. The atmosphere has always been involved in electromagnetic propagation. Wind, temperature, humidity, and dust are all part of the circuit."

The starlight behind the door began to recede, and the formula on the blackboard turned into tiny specks of light.

Jiang Ming memorized the last three sets of correction coefficients and withdrew his consciousness from inside the door.

The last trace of dark gold lettering in the Tongtian Record faded away along with the door.

[Remaining safe full-power output time for Yuanlei-1: 10 minutes and 50 seconds.]

Less than two seconds had passed in the outside world.

Fang Xudong's hand was still on the disconnect switch, and the echo of his question from earlier still lingered in his mind.

"Don't switch yet. The first ignition only took ten seconds. Source Thunder One still has ten minutes and fifty seconds of safe output time left."

Jiang Ming opened his eyes, tossed the sand in his palm into the air, and the fine sand was lifted up again by the upward airflow, then drifted away in a northwest direction.

He walked to the toolbox, pulled out an adjustable wrench, pried open the latch, and headed straight for the antenna bracket.

"Master Sun, loosen all four fixing bolts on the base and remove the spindle locking pin as well."

Old Sun had already put the first bolt on the socket wrench when Fang Xudong rushed back from beside the generator.

"Wait, why are you loosening the stent?"

"Change the elevation angle."

"The current elevation angle is the factory calibration value. The main beam and the power supply point are installed at zero degrees. Forcibly raising it will twist the support. Once the standing wave ratio exceeds three, the reflected power can burn out the magnetron."

Fang Xudong stood in front of the main shaft, the slide rule in his hand still in his pocket.

"There was only one Yuanlei No. 1. The first time it missed, it could still be brought back to Beijing. After it was burned, there was no chance to try again."

"The support frame allows for a pitch of ±15 degrees. The factory locking mechanism is a transportation requirement, and the main beam will not deform."

"This is not included in the instruction manual."

"The drawing shows that the arc length from the fulcrum to the limit groove corresponds to a 30-degree stroke, and the four fixing bolts are only responsible for locking."

Jiang Ming inserted the wrench into the adjustment slot below the main shaft, stepped on the heel of the bracket with his left foot, and braced his shoulder against the antenna frame.

Fang Xudong reached out and grabbed the main beam.

"Even if you can carry it, how much are you prepared to carry? It's all flat ground ahead, and if you try to raise the signal high, you'll only end up going over the mine shaft."

"So we need to let it go up first."

"Where to?"

Jiang Ming didn't answer again, but turned his head to look at Lao Sun.

"The bolt has been loosened."

With a turn of the socket wrench, the first bolt came off two turns, followed by the second and third bolts, while the last bolt still had half a turn of thread to support the base.

Fang Xudong glanced at Lao Sun, then at the antenna that had begun to tilt, and exhaled rapid white breaths from his nostrils.

"Master Sun, are you going to follow his reckless actions too?"

"If Engineer Jiang tells me to loosen it, I will loosen it. If the scaffold is broken, I will fix it; the pipes won't break."

Lu Qinghe stood behind the direction finding compass, the earphone still hanging on her left ear, her right hand already touching the elevation scale.

"What temperature do you need?"

"First, reset the direction finding reference to zero, then record the beam feedback, and keep the azimuth at 314.6 degrees."

"What about the elevation angle?"

"Seven o'clock two degrees."

Lu Qinghe paused on the dial with the pencil in her hand, her gaze passing over the antenna to the dark Gobi Desert two kilometers away.

"At 7.2 degrees, the antenna can reach more than 60 meters. The antenna in Mine No. 04 is less than 12 meters off the ground."

"Record it as I say."

Director Wang's voice came through the walkie-talkie.

"Tuqiu, please report the situation. Why did you loosen the antenna support?"

Lu Qinghe pressed the call button, her eyes still fixed on the spot where Jiang Ming's shoulder was pressing against her.

"Engineer Jiang requested that the physical elevation angle be changed from zero degrees to 7.2 degrees in preparation for the second ignition."

There was a few seconds of silence on the other end of the command post, with the sound of papers turning and distant telephone ringing mixed with static.

"Fang Xudong's opinion."

Fang Xudong gripped the main beam, his Adam's apple bobbing.

"I object. Existing propagation models do not support this angle, and the antenna support is also at risk of deformation."

"Jiang Ming, how confident are you?"

"The beam can cross the sand dunes and enter the mine's receiving port, with an 80% success rate."

"in accordance with."

Jiang Ming looked at the sand and dust that had not yet fallen from the sky.

"inversion layer."

Director Wang did not ask for the formula again, nor did he request a written explanation.

"Second ignition is permitted. Jiang Ming will be in charge of the equipment. Fang Xudong will continue to monitor the VSWR. Power will be cut off immediately if it exceeds 2.5."

Inside the mine's listening room, the bright line on the pulse oscilloscope had fallen back to the baseline. No second pulse was transmitted from the northeastern mound after the first impact ceased.

The detector kept the attenuator at the original setting and waited a few seconds.

"There are no new signals from the direction of the mound; they may be checking their equipment."

The technical supervisor walked up to the oscilloscope and glanced at the baseline that remained fixed.

"We missed the first time, and we couldn't find a new path. We'll continue with full-power frequency sweeping."

At the top of the mound, Lao Sun pulled out the main shaft locking pin, and the fourth bolt also came out two turns.

The wind was hitting the steel frame from the side, and for every half degree the main beam of the antenna was raised, the weight on Jiang Ming's shoulders increased.

"6.4".

Lu Qinghe stared at the dial, her pencil following the movement of the pointer.

A gust of wind struck the oscillator array, causing the support to deviate 0.2 degrees to the west. Old Sun grabbed the base and used a sleeve to hold the azimuth gear plate in place.

"Six point eight, four points short."

Jiang Ming waited for the wind to subside briefly, then took a half-step forward with his knees and used his shoulders to support the steel frame over the last limiting groove.

"7.2".

"Lock!"

Old Sun's socket has already engaged the first bolt.