Team Leader Zhu studied radar, worked hard day and night in radar technology, and finally reached the level of the 60s abroad, and the technical level of this 204 radar is almost the same as the radar equipped on the MiG-21MF.

However, Team Leader Zhu didn't understand airplanes, he just designed each circuit board into a definite shape according to the requirements of the 601 Institute, which could be stuffed into the space reserved for them, and met the heat dissipation needs and so on.

They designed the goal to search for a distance of 30 kilometers, accurately intercept the target, display it on the screen, and guide their own missiles at the same time.

Now the missile has not come out, let alone guidance, it can search for the target, at that time it was done countless times on the ground, and now there is a problem as soon as it goes to the sky, it turns out that it is the influence of ground clutter!

The apron here is hardened, the cement floor, Qin Feng picked up a fragment of a red brick, rubbed it on the ground a few times, and drew a triangle.

The maximum downward viewing angle of the radar is drawn with two lines with the water surface, plus the height, so that the distance can be calculated.

"The height is two thousand, this is the vertical height of the triangle, and the depression angle of the opposite radar is about thirty degrees, so that according to the calculation of the sinusoidal value, the hypotenuse is four thousand meters, and our radar search range is thirty kilometers, which has been far exceeded."

You don't need advanced math to explain the problem with a simple triangle.

204 radar, the angle of rotation of the universal joint on the antenna is certain, for subsonic targets, the lateral maneuverability is strong, the radar interception range is wide in azimuth and narrow in elevation, that is to say, its maximum angle in the horizontal direction can reach 120 degrees, but there are only 60 degrees in the vertical direction, so according to the horizontal line, it is 30 degrees, countless radar waves have hit the ground, and the echo must be dense.

Now that Qin Feng drew a triangle like this, he calculated it directly, threw away the remaining red brick fragments written in his hand, and Qin Feng said: "Why don't you limit it in the circuit and reduce its depression angle?" ”

Since looking down will make you blind, don't look down, add a special control circuit.

"No, no." Immediately, there was opposition.

This radar antenna is driven by a motor, and it would be nice to control it in the circuit, why not?

Qin Feng looked at this person, he was specifically responsible for the antenna, he kept shaking his head: "No, no, this will complicate the circuit, we can't make the circuit more cumbersome, so the failure rate will be higher." ”

If it is a radar of later generations, it uses digital circuits, then just add a few instructions in the program, it is very simple, such as reading the flight altitude, and when it is low, make the depression angle of the radar smaller.

However, not now, this 204 radar uses an analog circuit to the letter, adding a function, it will add a lot of circuits, how to integrate with the existing circuit, it is a test of technology.

The equipment of the Soviets, individual subsystems are not advanced, but together they are the most useful, which is how strong their integration capabilities are.

Now, we don't have this level, and if we add some more circuits, maybe the progress will drag on for a year!

You must know that to deal with subsonic targets, it is necessary to be wide on both sides and narrow at the top and bottom, and to deal with supersonic targets, the radar beam is exactly the opposite, narrow on both sides and wide at the top and bottom, and this circuit must be quite complicated.

He strongly objected.

This is the most direct way, but it can't be used now, Qin Feng also frowned.

Carrying a flight helmet in his hand and wearing an anti-load suit, Qin Feng and everyone else were all looking at the radar antenna in the nose, if the circuit is not changed, how to solve it?

Everyone was at a loss, Qin Feng paced back and forth, and Mr. Gu also followed.

"Qin Feng, what happened to the test flight?"

With the increase in the number of prototypes for test flights, Mr. Gu was also busy, and just after processing the data of the previous aircraft, he saw that the air intake cone of this aircraft was removed, and he knew that there was a problem.

"Our radar is jammed by ground clutter and cannot work normally." Qin Feng said.

It's not my own business, it's my radar's business.

Fighters, you need to have weapons, the previous J-7, the cannon is the main attack weapon, the old optical sighting system can also be used, but the current J-8 is different, it wants to intercept bombers, must use radar-guided missiles.

The supporting Thunderbolt-4 missile is under development, and if the J-8 fighter cannot use radar, it has a gun but no ammunition.

Mr. Gu also frowned, and asked Team Leader Zhu, "What is the reason?" Did you find it? ”

"Qin Feng has analyzed it for everyone, and we think it makes sense."

Pointing to the triangle drawn by Qin Feng on the ground, Team Leader Zhu introduced: "Look at this triangle, even if it flies at an altitude of 10,000 meters, a considerable part of the beam of our radar will be shot on the ground. ”

Team Leader Zhu made a few gestures, and Mr. Gu understood, and he also felt that it was difficult to deal with.

Qin Feng looked at the vertical air intake cone on the ground again, and suddenly, something came to mind in his mind.

"There it is!"

Qin Feng said.

"What's up?"

"Mr. Gu, our plane last time was similar to the air intake cone of our J-8, right?" Qin Feng asked towards Mr. Gu.

Mr. Gu nodded: "It's smaller than ours." ”

The MiG-21MF is a secret, and the people present don't know, but Mr. Gu knows that Qin Feng is talking about that plane.

The two characteristics of the MiG-21MF, one is the backbone, the other is the air intake cone, when I arrived at the 132 factory, I began to disassemble the mapping, I have studied the air intake cone for a long time, I was a little confused, and now I suddenly realized.

"After dismantling, the lower part of the air intake cone, there is an extra layer of black stuff, which is elastic to the touch, and I asked at the time, and someone said that something tens of square centimeters is a special layer of conductive rubber."

In order to let the electromagnetic waves pass through, the air intake cone is generally made of organic materials such as fiberglass, and the metal is shielded against the electromagnetic waves.

And this conductive rubber naturally blocks electromagnetic waves, why is it in the lower half?

Qin Feng was puzzled before, but now that he encountered technical problems, he recalled this scene, and then looked at the picture he had just drawn on the ground, and suddenly realized.

The Soviets are the smartest, they have always used the most direct way to solve the problem, in later generations, when the domestic research and development of the Red Flag Nine, there were a lot of technical problems, obviously the domestic level of science and technology has been much higher than that of Russia, but it is impossible to complete the research and development of the project.

Later, the S300 was imported, and when I opened it, I suddenly realized that I just needed to do it!

When I saw it, I thought it was the most ingenious thing to do, but if I let myself think about it, I couldn't think of it anyway, and this is the cleverness of people!

Qin Feng picked up the fragment of the red brick he threw away, and at the top corner of the hypotenuse of the triangle, he drew a horizontal line fiercely: "The solution is very simple, let's block it here!" ”