Transmigrated as the Crown Prince

Submarines, as the core of underwater power, often deal with and compete with powerful enemies under seemingly calm seas.

But this also leads to a very obvious problem.

You must know that seawater is equivalent to a huge conductor and has a good electromagnetic shielding effect. Therefore, a submersible submarine can hardly receive any television signals, mobile phone signals, wireless network signals, or most military radio communications.

So how should the submarine keep in contact with the command? Float to receive and send messages?

This was a dead end in the late World War II. As soon as the submarine surfaced, there was a high probability that the submarine would be targeted by anti-submarine aircraft.

Therefore, the communication problem of submarines has become a worldwide problem.

When submarines became an independent combat force, in order to solve the communication problem of submarines, the navies of some countries used surface warships escorting submarines as relay information stations. After the information was transmitted to the surface warships by radio, the warships then used Sounds are emitted underwater through firing and other means, and are received through sonar on the submarine. This method was gradually abandoned after the First World War due to its high distortion rate and almost no confidentiality.

There is also a method of sending and receiving information through radio buoys, but when using radio buoys, the submarine needs to remain relatively stationary in the ocean, and then send the buoys connected to the communication equipment on the ship through wires to the sea surface, and then receive radio signals through the buoys.

This device solves the problem of communication between the submarine and the outside world, but it is still highly restricted: the submarine needs to remain suspended underwater, so it is easier to be discovered and attacked, which reduces the submarine's survivability. In addition, radio buoys are relatively fragile and may be damaged in harsh environments.

At the end of World War II, communications experts discovered a way for submarines to receive communications underwater: long-wavelength stations.

Seawater has a strong absorption effect on electromagnetic wave energy, but it has different effects on electromagnetic waves of different wavelengths. The shorter the wavelength and the higher the frequency, the greater the attenuation in seawater. But electromagnetic waves with longer wavelengths can penetrate a little bit of sea water. The longer the wavelength, the stronger the penetrating power of electromagnetic waves. The signals sent by very long wave and ultra long wave radio stations can enter water from tens to more than 100 meters.

Long-wave station is a general term. In fact, electromagnetic waves with a wavelength of 1,000 to 10,000 meters are called long waves, electromagnetic waves with a wavelength of 100,000 meters to 1 million meters are called very long waves, and electromagnetic waves from 1 million meters to 10 million meters (10,000 kilometers) are called ultra-long waves. .

Very long wave radio stations can penetrate more than 20 meters of sea water. At the end of World War II, the German Navy had already begun to develop a very long wave communication system. The submarine does not need to surface and can receive very long wave telegrams from the command at periscope depth. It’s just that the periscope depth is still not safe enough for submarines.

The ultra-long wave radio station can penetrate 100 meters of sea water, which is also the normal navigation depth for submarines to prepare for combat cruising.

Therefore, what people collectively refer to as long-wave stations are actually the most commonly used very-long-wave and ultra-long-wave stations.

But the problem is that building a long-wave station is no small project. How big is the antenna of the long-wave station?

It can only be said that it is a very big and huge thing; if you build a tower more than 100 meters high, it is only a small part of the long-wave station antenna!

Because the antenna of the long-wave station is too long, it is not vertical but "lying horizontally". The function of the tower, which is more than 100 meters high, is to isolate the antenna body from the earth as much as possible to prevent the signal quality from being interfered by ground waves when the long-wave station transmits.

The United States built a long-wave radio station in 1986. The radio station consists of two parts. One part is located in Wisconsin and the other part is located in Michigan. The two places are 258 kilometers apart. The two parts can work jointly or separately. Its antenna has a total length of 135 kilometers and a total of 8 transmitters, half of which are working and half of which are standby, with a total power of 28 megawatts.

It is 135 kilometers and takes more than an hour to drive.

Why is it so long... Because the radio waves sent by the long-wave station have a very long wavelength; the length of the antenna is generally one integer multiple of the wavelength, and the length of the antenna is closely related to the quality of signal transmission.

Ultra-long wave radio stations with a wavelength of 1000 kilometers generally use 1/8 wavelength antennas, which means the antenna length is... 1000÷8=125 kilometers. It is not impossible to use a 1/16 wavelength antenna, but the signal quality will not be that high.

Yannick hesitated before agreeing to build a long-wave radio station.

At this time, the German submarines cruising in the North Atlantic received telegrams from the Wolf Pack Command.

"Captain! Call from command, another prey has been found."

The captain took the telegram, glanced at it, and his eyes lit up. "Nearly two hundred transport ships? What a big guy." After comparing the distance on the navigation chart, he went to the periscope and observed the surroundings before ordering. "Come up! Go at full speed!" Their current location was a bit far away from the ambush point, and they would definitely not be able to catch up while underwater.

With waves of shaking, the submarine slowly surfaced, swaying and rising and falling with the waves on the sea.

"Pay attention to the surrounding areas!"

A sailor stepped forward and unscrewed the hatch cover of the bridge. The remaining seawater poured down in the fierce sea wind, and the people around him shivered. Due to the operation of power and mechanical equipment, the interior of the submarine maintains a high temperature of more than 30 degrees all year round, just like the hot Sahara Desert.

The sailors put on cold-proof coats and climbed out of the bridge along the ladder to the deck, smoking while observing the surrounding sea conditions.

And the cold sea breeze kept pouring into the submarine, sweeping away the unpleasant smell inside the submarine.

Submarines during World War II did not have the advanced air filtration devices of later generations, and the smell inside them was quite unpleasant. The smoke from the diesel engine, the smell of rotten food, the odor in the toilet and the sweat on the crew... It is not difficult to understand why cologne is so popular on German U-boats.

"It's so cold!" The two shirtless sailors in the submarine's power cabin shivered violently and hurriedly found some clothes to put on.

The high level of belief and fighting spirit of the officers and soldiers of the German Navy's submarine force is the basis for maintaining a high level of self-discipline and mutual trust. In this case, military discipline itself is often not that important. Some German captains, who are known for their strict discipline, also have relatively loose standards for the enforcement of discipline on board.

The combat attire of the German Navy's submarine force crews was originally the traditional navy blue uniform, but it was not comfortable to wear in such a small space as a submarine. Therefore, in the view of most German captains, as long as the crew members can effectively perform combat missions and are highly competent, they can choose their own clothing.