Siheyuan: I eat melons while doing scientific research

Chapter 1332 gave too much; we can't be greedy. (4k)

The thing Gao Zhendong was talking about is actually not unfamiliar to military enthusiasts in the 21st century. It is the music station radar from the White Bear, or more precisely, it comes from the most cost-effective military purchase in the world in the 20th century—the introduction of the 956 "Sovremenny-class" destroyer.

It's no exaggeration to say that the 956 deal is the most cost-effective military purchase in the world, bar none. Of course, the premise is that one has the ability to fully utilize the 956, and not just use it as a relatively advanced destroyer. For example, some powerful nations have struggled to fully utilize even decades-old SAM-6 destroyers, which is a different story altogether.

Whether a business deal is worthwhile depends on one's own capabilities; that's just how realistic the world is.

It was through this arms purchase that we established a truly effective air and sea offensive and defensive system, which includes not only defense but also offense, or at least effective beyond-visual-range offense.

A crucial element of this beyond-visual-range attack is the Music Station radar, not the Sunburn anti-ship missile with a range of only 80 kilometers before its improvement. The performance of that anti-ship missile was mediocre at best; calling it a carrier killer was probably just wishful thinking.

However, a common misconception is that "Music Station" is a skywave radar. In fact, it is not. Although the two are somewhat similar, both achieving their purpose through the special reflection of radar waves by atmospheric structure, there are significant differences between them.

"Atmospheric waveguide? Chief Engineer Gao, that sounds a bit like skywave radar." This is precisely where atmospheric waveguide radar can be confusing. Not to mention ordinary people, even professionals would be confused when they first heard it.

Gao Zhendong shook his head: "There is a big difference between the two. To put it this way, if we use light as an analogy, the atmosphere in skywave radar acts like a mirror, while atmospheric waveguide radar acts like an optical fiber. Although this analogy is not very accurate, it is quite vivid."

After hearing this explanation, the comrades understood a bit better; so that's how it was. It was just so vividly illustrated.

No wonder Chief Engineer Gao started with optical fiber; it turns out it served this purpose. He used an example from outside the industry to vividly illustrate an industry matter to those inside. That's truly something else.

But you know what, the effect was really good! Chief Engineer Gao is indeed Chief Engineer Gao, always so unique. The fact that he made light bend and move forward in a predictable way left a very deep impression on everyone; the feeling of awe is universal, regardless of whether one is an expert or not.

After explaining this analogy, Gao Zhendong added, "The electromagnetic wave reflecting surface of an atmospheric waveguide is a region in the atmosphere where air density changes abruptly due to weather, temperature, and other factors. Anyone familiar with atmospheric refraction knows this. When observing space targets from the ground, the location is not very accurate because of atmospheric refraction caused by differences in atmospheric density. As anyone who has studied physics knows, when the angle of incidence is large enough, this refraction becomes similar to total internal reflection, which is similar to total internal reflection of light in an optical fiber... I've calculated that, theoretically, with current technology and under usable conditions, the detection range of atmospheric waveguide radar against ships is approximately 200 to 400 kilometers!"

The example was vivid, and the principle was actually known to everyone, but they hadn't considered it in this direction before. Gao Zhendong's explanation of giving an example first and then explaining the theory made the comrades at the radar institute realize what was going on.

The comrade from the Naval Equipment Bureau wasn't very interested in the previous part, or rather, he didn't quite understand it, but he was very good at numbers! He only remembered that one number!
"200-400 kilometers? Oh my, 200 is enough, 200 is enough!" He was so happy he couldn't stop grinning. He threw all the worries about weather restrictions, false alarms, and susceptibility to interference aside. Distance was everything! They even felt a little embarrassed, thinking that 400 kilometers was too much and that was about right.

The colleagues at the radar institute had a slightly different concern. They understood a little, but new worries arose: "But if that's the case, we know that the optical fiber you're working on requires active means to extract the light. Otherwise, it can only be emitted from the optical fiber at the end of the optical guide material. However, for radar detection, we don't have the means to actively extract electromagnetic waves from a distance. In other words, this electromagnetic wave will forever travel in the atmospheric waveguide and will never have a chance to contact enemy ships on the sea surface."

Upon hearing this, Gao Zhendong realized, "Oh no, I've gone too far with my image..."

He still had to draw, so Gao Zhendong picked up the chalk.

"Here's the thing, the upper reflector of this atmospheric waveguide is a region in the atmosphere where the air density changes abruptly due to weather or other reasons, but the lower reflector is not another layer of atmosphere, but the sea surface..."

If you still haven't grasped this yet, then there's something wrong with your head.

"Ah... I get it!! I'm so stupid, hehehe~~~~" The comrade from the radar institute was a little embarrassed. It couldn't be blamed on Chief Engineer Gao for giving such a vivid example.

In this way, both the radar and the target are within this atmospheric waveguide, eliminating the need to extract electromagnetic waves from within the waveguide. Similarly, the target's reflected echo also returns within this atmospheric waveguide.

After figuring out this set of principles, the comrades couldn't help but applaud in admiration.

"That's an amazing idea!"

"By using atmospheric waveguides to lower the height of the reflector layer, the blind zone problem of skywave radar has been solved."

"This atmospheric waveguide will have to use the microwave band, right?"

"That's for sure. In principle, the reflection efficiency of shortwave bands in the atmosphere is definitely not as good as that of microwaves."

"Microwave band is good. At least the antenna size doesn't have to be as exaggerated as shortwave, and it has the practical capability to be deployed on ships." Just like the phrase "minor injury is not minor and serious injury is too serious" that is often mentioned decades later, because the speed of light is too fast, the "shortwave is not short and longwave is too long" of electromagnetic waves is also a headache for those who work in radio frequency.

"Moreover, the accuracy of the microwave band is even better, so it's a win-win situation."

"This is promising! Although it can't work around the clock, as long as it works, this thing is a miracle."

"..."

Hearing his comrades' discussion, Gao Zhendong smiled and said, "Actually, through certain means, we can also increase its usable time. Although we can't completely solve it, we can solve a considerable part of it."

Upon hearing this, the comrades from the Naval Equipment Bureau widened their eyes like copper bells, realizing that all the defects and flaws Chief Engineer Gao had mentioned were tests for them. It was just like... yes, that Journey to the West, where people had to be tested before they could obtain the scriptures.

It's true that there are flaws, but it's clear that others have long been prepared with countermeasures. It's impossible to solve everything, but even solving just a little bit and increasing the available time by 10 or so percentage points would be a leap forward.

It seems that our strategy of sticking to our guns and not letting go was the right one!
"Chief Engineer Gao, do you have any other good ideas?" The comrades at the Radar Institute were even more anxious than he was!
Gao Zhendong laughed and said, "Actually, there are two methods for this: active detection and passive detection! Atmospheric waveguides are effective against our electromagnetic waves and also against the enemy's electromagnetic waves. The only difference is that we utilize these atmospheric waveguides, while the enemy does not. Regardless of whether they are utilized or not, the transmission of electromagnetic waves must follow the laws of physics."

"You mean, we can use this atmospheric waveguide to detect enemy radar signals and thus locate the enemy?" It was all so clear; how could the comrades not understand? Gao Zhendong nodded: "Yes!"

One colleague thought about it and found a bug: "Chief Engineer Gao, but when the conditions for using atmospheric waveguides are broken, it's impossible to use this principle for transmission and reception, whether active or passive, right?"

It's like this: whether it's a light bulb that emits light actively or a mirror that emits light by reflection, if there's a wall between your eyes and the target, you won't be able to see the light emitted by the target.

Gao Zhendong nodded: "Yes, that's the principle, but the reality is different. First of all, let's be clear: if we're going to develop a microwave atmospheric waveguide radar, then the radar's bandwidth needs to be wide enough, for reasons I think everyone knows."

That's clear to everyone. We should make the most of atmospheric waveguides under various conditions, so naturally, the more wavebands the better.

"Under these conditions, the microwave radar waves of enemy ships can propagate under atmospheric waveguides under certain conditions, thus increasing the probability of being intercepted. We know that what is unusable for one band of the atmosphere may be able to form an atmospheric waveguide for another band."

To put it bluntly, it's all about luck and relying on band coverage. But you know what? When the band coverage is comprehensive enough, the probability of getting lucky is not small.

"Ah, yes, the difference between theory and practice is indeed evident. Practice is much more complex than theory. Chief Engineer Gao, you have considered things more comprehensively."

The comrades from the Naval Equipment Bureau were overjoyed, thinking that the deal was about to be finalized.

"However, wouldn't this place too much demand on the radar? The more bands there are, the greater the cost. It's like adding more water when there's too much flour, and adding more flour when there's too much water. There's limited space on a warship."

This is true. The more bands a radar wants to cover, the greater the cost will be. Even disregarding factors such as cost, difficulty, and complexity, size and weight alone can be a major issue.

Oh no! The mood of the comrades from the Naval Equipment Bureau took a sharp turn for the worse.

Gao Zhendong laughed: "Hey, let's not be so rigid. Sun Wukong has a skill called the clone technique, we can create clones too!"

"A clone? Does that mean using several ships, each equipped with radars covering different frequency bands?" The comrades at the radar institute knew that Chief Engineer Gao could sometimes really make do with what he had, and he might not be incapable of coming up with such strange ideas.

The comrades from the Naval Equipment Bureau didn't seem to find it unacceptable, mainly because the temptation of beyond-visual-range strikes was simply too great.

A 200-kilometer beyond-visual-range strike capability means that, under the protection of shore-based air forces, the enemy can be pushed back to a distance of 600-1000 kilometers in one fell swoop. Even without the protection of shore-based air forces, relying on the increasingly clear and exaggerated anti-aircraft missiles of air defense ships, they still have the ability to fight the enemy at sea.

Unexpectedly, Gao Zhendong laughed: "No, no, what I meant by 'cloning' is disassembling the radar. For active radar, we can select only the best bands, thus balancing the shortcomings of multi-band coverage with the performance limitations. As for passive detection radar, since it doesn't require active transmission, the radio frequency section is much simpler, allowing us to cover as many bands as possible and focus our resources on reception and back-end processing to achieve maximum effectiveness!"

Holy crap! Chief Engineer Gao's integration capabilities and approach to engineering applications are absolutely amazing!

At this moment, the comrades only regretted their lack of education, and could only say "I'll fuck you all the time."

If one is to launch proactively, then the best steel should be used where it is most needed.

A passive receiver is much simpler in the radio frequency section, so the focus should be on expanding the frequency band and back-end to improve the detection effect.

It's a pretty simple method, but I just couldn't think of it.

"This method is brilliant! Apart from the need to consider electromagnetic compatibility between active and passive radars, it has virtually no flaws!" The comrades from the radar institute exclaimed in admiration.

Gao Zhendong looked at him with an expression as if he were an idiot: "There's no need to consider electromagnetic compatibility."

"Not needed? But the two have a high degree of overlap in their frequency bands, and the possibility of mutual interference is also very high." Passive radar must cover the frequency band of active radar, so it is impossible not to interfere.

Gao Zhendong laughed, a hearty laugh: "Don't think too much. We'll arrange the active and passive radars back to back. When the radars rotate, the active one will work, and the passive one can also work, and they won't interfere with each other, each doing its own thing."

The comrades all burst into laughter. This was an overcomplication of the situation. It was like playing chess, where the pieces are back to back and the generals don't even face each other.

"However, passive radar can only tell which direction there is an enemy ship, and the distance can only be estimated by the signal characteristics." A colleague from the radar institute had thought this through very deeply.

Passive radar only knows the azimuth; as for the distance, it can only rely on signal characteristics to determine the type of enemy radar, and then make a certain judgment based on the radar's transmit power and the degree of signal attenuation.

The comrades from the Naval Equipment Bureau didn't care about this. Chief Engineer Gao had already given them enough ideas, and they would be struck by lightning if they were greedy: "It doesn't matter. Knowing whether there are enemy ships in a certain direction is of great help to us. If we can make a rough estimate, it will actually be enough to support our operations."

If they weren't greedy, where would they have gotten all these good guys before?

“That’s true. Our electronic reconnaissance ships have been collecting various data. With this data, the accuracy of our estimations should meet your operational requirements.” The comrades from the radar institute were very clear about what the electronic reconnaissance ships could do and what they were doing. After all, some of their colleagues were conducting research on the electronic reconnaissance ships.

Gao Zhendong shook his head: "Estimation is necessary, but under normal circumstances, it can be more accurate."

What? Come on, let lightning strike me! The comrades in the Naval Equipment Bureau change their minds way too fast!
(End of this chapter)