Within 200 nautical miles of Namgundo Island, a short-wave anti-submarine radar defense ring is arranged.

Here we have to mention "active sonar" and "passive sonar".

Because active sonar is constantly emitting acoustic signals outward, the nature of the target is judged based on the echo. But the consequence of this is that when you detect an enemy submarine, you will also tell them your exact location.

This approach is more of a strong psychological deterrent.

In this case, in addition to warning the other side, you also tell the other party that you have been completely surrounded by our side and will die if you do not surrender.

Passive sonar, on the other hand, is a passive radar, because it does not actively transmit signals and only receives sound signals radiated by the target itself, so it is not easy to be detected by the enemy and is mainly used for covert reconnaissance.

If paradoxes can be applied to one thing, then I'm afraid it will be sonar.

In modern submarine warfare, it is 99.99% of the time possible to detect any enemy submarine when using active sonar. But at the same time, it also means that you are exposed.

Of course, Han Yi can make a "passive active sonar", but there have been a lot of things recently, and he didn't care about it for a while, how did he know that the other party actually came to the door?

And under the warning of active sonar, it continued to advance to 100 nautical miles, and it seemed that it was prepared.

Han Yi's face was cloudy, and he wanted the other party to go to the bottom of the Pacific Ocean to sober up several times.

But in this way, it is tantamount to poking a hornet's nest.

The submarine that can run to the South Pacific is definitely a nuclear submarine, and such a country will definitely have aircraft carriers, and once sunk it will mean endless trouble.

"Well, spare your lives first. ”

Then Han Yi ordered: "Send a robot over to see which country's submarine it is." In addition, warnings will be issued, and if they are not heeded, they will launch expulsion mines. ”

......

At the bottom of the South Pacific Ocean, rubies have reached less than 80 nautical miles.

At this time, the captain (equivalent to the political commissar) Brandon Byron and the first mate Tommy Robinson were discussing whether to move on?

Just ten minutes ago, an active sonar source was spotted again 30 nautical miles behind the left, which was a warning to them!

"Tommy, what do you say to do?"

Tommy Robinson is a radical person, looking at Nanjun Island on the navigation map, and he is very unwilling.

After thinking for two minutes say, "Go ahead." They should have simply laid out anti-submarine radars, and did not have means of attack. However, just in case, let Simmons prepare them for battle. ”

"......" Brandon Byron was cautious, and when he heard the battle, he hurriedly dissuaded: "This is absolutely not good. We just came to investigate, and we didn't receive an order to attack. And what you say is just speculation, if the other side has an attack weapon, it will be a disaster. ”

Robinson insisted on his opinion, "Don't worry about Brandon, as long as we don't take the initiative to attack, he will never dare to attack ...... first"

"Boom-"

"Ouch-"

Before Robinson finished speaking, a violent explosion suddenly occurred in the waters 2 nautical miles ahead, and the turbulent undercurrent swayed the submarine from side to side, and Robinson, who was standing in front of the instrument, fell to the ground violently.

"Sir, they fired an expulsion mine...... Oh no, here we go again......"

"Boom-"

Two successive expulsion mines exploded under the water, and the violent current swayed the rubies, and the crew of the submarine staggered.

"These *** really dare to attack...... Robinson scolded angrily, "Listen to my orders and fight back immediately." ”

"Sir......

Robinson gritted his teeth and said, "Attack!"

"Yes!"

"Listen to me......

Missile preparation ......

Target parameter 330XYT209......

Target ......

Launch ......"

"Bang ......"

There was a tremor from the submarine, and a well-known SM-39 "Exocet" submarine-launched anti-ship missile was fired at a range of Mach 0.9 at a huge humanoid undersea machine 20 nautical miles away.

However, what the people on the submarine did not expect was that the Exocet missile was intercepted 2 nautical miles away.

Looking down from the sea surface, you can find that the sea surface that was originally calm at night is already turbulent at this time, and the waves of white flowers are ups and downs;

At this moment, the center of the wave suddenly bulged up again, and then exploded violently.

"Boom-" The sea water suddenly jumped up to a height of ten meters, and the huge waves splashed out dozens of meters away, and the center point seemed to be evaporated and dried up, revealing a huge black cavern, which was then quickly filled by the seawater.

Seeing that the missile was intercepted, Robinson was also shocked and frightened, and ordered a full-speed retreat.

At the same time, Han Yi also knew the identity of the submarine.

......

"It was your ......"

Han Yi sneered.

There are a lot of rifts between the two sides on the Sagarata side. In order for his wife to mine gold peacefully, he sent 60 million US dollars out, most of which was taken by French-controlled power organizations.

Now the other party has come to his door and launched a missile, if he just let them slip away, he is really unwilling.

But you can't really sink it. In that case, the French government will have to go crazy, and then it will be endless.

Soon Han Yi thought of a way to blackmail the French government without sinking the submarine.

"Voiceprint Recording"!

As the most important feature of submarines, the voiceprints, especially those of underwater tactical silent navigation, can never be fully collected.

The background noise from the bottom of the sea is very complex, and it is quite difficult to search for the sound of a submarine inside.

In the past, the mute technology was not developed, and the continuous noise of the submarine's normal operation was relatively easy to hear directly with passive sonar;

With the popularization of modern shock-absorbing floating rafts, sound-absorbing tiles, and large roll propellers, this kind of continuous noise has been greatly reduced, and it is difficult to fish out the background noise of the ocean.

At this time, the voiceprint of a specific submarine is naturally needed as the basis for comparison and filtering.

So, once the voiceprint is in the hands of someone, this submarine will be like a stripping little girl, and there will be no secrets to speak of.

Under the sea, you haven't noticed anyone else, but someone else has discovered you. When the time comes, sneaking a missile at you will have unimaginable consequences.

At this time, in Han Yi's opinion, this ruby is the fat meat sent to the door.

......

Under the dark and deep ocean, the Ruby submarine is retreating at full speed.

Although he didn't complete the landing mission, knowing that the other party has a powerful interceptor weapon is also a great achievement.

If it weren't for the fact that he wasn't completely out of danger at this point, Robinson and the rest of the crew were ready to drink and celebrate.

It's a pity that Robinson didn't know that at this time, there was a robot lying on his stomach outside the submarine, with his palm attached to the submarine, collecting voiceprints and shock waves at 0 distance.

Ten minutes later, after collecting the complete voiceprint, the robot actively released its palm.

......

A week later, just as the French government was preparing to request the United Nations to launch a joint investigation into Nangundao in the South Pacific, the Naval Joint Operations Command received an email.

The mailbox of the French Navy Command is not open to the public, but is only used for internal communication, and this external email without an identification code appears very abruptly.

After discovering the email, the personnel of the headquarters office first asked the technician to isolate the email, and only clicked on it after confirming that there was no danger.

The content of the email is: I am a snorkeling enthusiast, and a few days ago I accidentally saw a strange big creature 600 nautical miles east of Fiji Island, and out of curiosity, I used the device I carried with me to record the wonderful sound of this big guy.

There is also an attachment after the text. It's about 5MB.

The office worker downloaded the file out of curiosity.

This is an audio file.

"Whoa...... Woowoo...... Uh-huh, uh-huh......"

When it was all over, the office staff and technicians all looked at each other, and they only heard a noisy background sound, and nothing else.

In the end, the office staff found his supervisor Smith, who naturally had a different vision, and immediately heard that this was the voiceprint of the submarine, and then combined with the content of the email, his face suddenly changed greatly.

"Quick, copy this audio to me. In addition, this computer does not have my approval, and no one is allowed to touch it. ”

Soon, the director of Smith hurriedly went to the superior supervisor with an encrypted USB flash drive.

In less than half an hour, the USB flash drive was placed on the desk of the commander-in-chief of the French Navy, Nick Alexander, and he also knew the origin of the voiceprint - the ruby attack nuclear submarine!