Bismarck

"Yes, for example...the next exercise..."

However, the second subject exercise is about to begin...

Just when Goering thought that the so-called electronic interference was nothing more than that, suddenly, large flakes of snow appeared on the radar screen!

Covering interference, using their own radar to modulate interference waves of the same frequency as Zeppelin's radar! Although the Zeppelin radar operator quickly moved the radar antenna away from this angle, allowing the radar to resume normal operation. But obviously, this would make it impossible to detect the enemy's situation.

Goering changed several channels without giving up, but this time was completely different from the last time. He changed several channels, but there was no effect!

This direct observation of electronic interference amazed Goering. Pointing at the snow on the screen, he asked, "It's really amazing. Is there any way to eliminate this effect?"

"This is still quite difficult, because the jammer only needs very small power to suppress a radar with much greater power, so it is still very troublesome..." Zeppelin said with difficulty.

"Oh? Why is that?" Goering asked curiously, but soon added: "Please explain it simply!"

In a word, Professor Wolf, who wanted to explain in professional terms, had to retreat in embarrassment. He thought that Goering would beat him up as soon as he explained...

But this did not pose a problem for Zeppelin. She had already discussed with Bismarck in private how to explain Goering, so she was well prepared.

"It's like this. Although our radar has great power, the signal strength it returns is actually not that strong." In order to make Goering understand, Zeppelin gave an analogy that Goering could understand more easily: "It's like a searchlight. The power of a searchlight can be tens of kilowatts, but even so, the enemy planes it illuminates will only appear to us as a small point of light far away, even in the dark night sky, not as bright as a light bulb at home."

"Is that so... In other words, only a low-power jammer can interfere with a much more powerful radar?" Goering was quite interested. The German radar tube power was not as good as the British, but if this method was effective, at least it meant "I can't see you, but you can't see me either!"

"Yes."

“Is there a way to crack it?”

"This can only be solved by changing the frequency band... In theory, the adjustment range of the radar's electromagnetic wave frequency is limited. If a radar can have multiple frequency band transmitters, transmit multiple frequency bands, or even have equipment that can continuously switch frequencies, it is possible to resist this interference to a certain extent. But unfortunately, there is no such equipment now, and it is not ruled out that the enemy's jammers also have multiple frequencies... In short, this field may require continuous research..."

"And in addition to this, another jamming method will be demonstrated next: chaff scattering."

---

As early as before World War II, British experts proposed a plan to use balloons to hang metal dipoles to interfere with German radar. The so-called dipole is actually a metal wire with a length equal to half the radar emission wavelength. This length is the most effective length for transmitting electromagnetic waves (in fact, the dipole transmitting antenna is composed of two quarter-wavelength, opposite-vector short metal wires to form a half dipole), but this length is also the most effective length for interfering with electromagnetic waves! Therefore, throwing a large number of "metal wires" can have the effect of interfering with radar.

In 1941, Britain officially launched an experiment to use metal strips for radar jamming. Experiments have shown that a bundle of 240 22*14 cm tin foil strips can produce the echo of a Blenheim bomber, and when dropped at an altitude of 3000 meters, the chaff cloud will continue to affect the radar for up to 10 minutes, and dropping 1.6 bundles of such chaff strips at a depth of 10 kilometers can saturate the radar screen!

However, because the chaff technology was too simple and (before the advent of centimeter-wave radar with magnetrons) would interfere with the Allies' own radars, it was once banned by the Allies. The first to use this trick were actually the Axis powers. In May 43, Japan dropped "deception paper" made of metal mesh in the air battle on Bulgaville Island. At about the same time, German submarines were also equipped with "butterfly" radar deception buoys composed of hydrogen balloons and three 5-meter-long aluminum foil lines. The principle was basically the same as that of chaff. After the Allies were equipped with centimeter-wave radars with shorter wavelengths on a large scale, when the wavelength was smaller than the gap between chaff strips, the interference of chaff strips would have a probability of being "seen through", that is, from the end of 5, Britain began to stockpile and use chaff strips on a large scale.

However, the Germans were now ready to use chaff jamming for the first time!

This was a historic moment. Bismarck had already changed history enough, and she didn't mind changing it again. As a pragmatist, she would not be like the protagonists of other time-travel novels who were afraid to make changes to history. In fact, she actively participated in it.

Because if you don't change you will die.

As the foil strips dropped by Zeppelin's JU87 were scattered by the wind at an altitude of meters, Goering, who was sitting in front of the radar screen, was shocked to find that the lonely green light spot on the screen had instantly turned into a large target echo! On the radar, it looked no different from a large-scale bomber group that suddenly "appeared"! If Bismarck had not reminded Zeppelin in advance and reported the effect of the foil strip interference to Goering in advance, I'm afraid the Imperial Marshal would have shouted at the top of his voice for air raid alert.

Goering was very happy when he saw the large reflection wave suddenly appearing on the screen. In this way, the probability of breaking through the Strait of Gibraltar would increase greatly. But soon, the Imperial Marshal realized a more terrible problem:

"Electronic jamming is so powerful, but... the British have stronger radar than us, and have actually used electromagnetic jamming... If they jam us on a large scale, what should we do?"

Zeppelin couldn't help but glance at Professor Wolff behind Goering, but she found that Professor Wolff was also looking at her with almost the same eyes...

But Zeppelin had no choice. She and Bismarck looked at each other and then spread their hands helplessly.

Bismarck and Zeppelin were only responsible for creating this phenomenon so that they could safely pass through the Strait of Gibraltar. As for this kind of interference that did not distinguish between friend and foe, it had nothing to do with them because their detection methods did not require radar.

"...Unfortunately, with our current means, there is no way to deal with it for the time being... The length of these foil strips corresponds to the wavelength of our radar waves, and at an altitude of 3000 meters, these foil strips can float for a full ten minutes before being completely blown away. Before the foil strips are blown away, the electromagnetic waves of our current radar cannot penetrate these dense foil strips, so it is very troublesome..."

"If we can't crack it now, what about the British?"

"Well...their radar can achieve a shorter wavelength than ours, probably only in centimeters...The density of the chaff cloud dropped can be perfectly reflected in front of our current meter-wave radar, but the centimeter wave can pass through the gaps between the chaff strips...Although there will definitely be some obstruction, it can still be used to detect targets, and we won't be blind like we are now..." Zeppelin considered his words for a long time before he spoke carefully while looking at Goering's face.

"Britain has developed magnetrons that can be used on a large scale?!" Goering hadn't said anything yet, but Professor Wolff from the German Air Force's Electronic Technology Department, who was following Goering, shouted out in surprise.

"Magnetron?! What is that?" Goering was stunned. Professor Wolff then remembered that he was an authority on electronic equipment, but Goering was not...

"Oh, sorry, Your Excellency the Imperial Marshal, let me explain..." Professor Wolf, knowing that he had made a mistake, explained with embarrassment.

ps: I promise... "Girls Are Nan" is absolutely not poisonous~23333

Chapter 379: The Cheating Ship Girls

It turns out that centimeter-wave radar must use an ultra-high frequency signal source to work. Before the invention of the magnetron, the conventional oscillator circuit could only increase the frequency to 600 MHZ, which is a wavelength of 0.5 meters. At that time, 1.5-meter wavelength (200 MHZ) was more commonly used for sea detection, while the frequency of air detection and large-scale search radar was generally 100 MHZ (3-meter wavelength) or even lower. This is because the detection distance of long waves is farther at the same power, so there are even many 4-7-meter search radars - this so-called long-wave radar is like a nearsighted person, who can only roughly detect the target as a means of general positioning, and for controlling weapons, it is already powerless due to insufficient accuracy.

The key to higher frequencies is the magnetron.

Of course, they had already appeared in laboratories as early as 1921, but early magnetrons had several major problems and could not be used properly.

As early as the mid-30s, scientists from several countries discovered that by controlling the frequency of the anode current so that the phases between the two slots are exactly opposite (called π mode), most electrons can be kept active in the gap in the middle and will not be absorbed by the frequency-controlled cathode. This structure greatly improves the effective power of electrons, from one or two kilowatts to tens or even hundreds of kilowatts! It can also transmit ultra-high frequency signals from meter waves to centimeter waves and even millimeter waves, and its size and weight are much smaller than traditional meter-wave radars.

It is no wonder that this technology was classified as an absolute secret as soon as it came out. It was only "secret" for less than half a year before Churchill gave it to the United States for free...

At this time, the British centimeter wave radar had also begun to serve. In May 1941, the British 5 search radar was successfully put into use on the British Royal Navy Flower-class frigate Red Gate Lan. The wavelength was 271CM, and the destroyer type had a power of 10KW. It could detect submarines sailing on the surface at a distance of 5 yards, or detect periscopes at 5000 yards. The model used by large battleships has a maximum power of 1200KW and can detect large battleships at a distance of 90 miles...

And although meter-wave radar is sufficient for distance and direction finding of warship fire control, centimeter-wave radar can detect the echo of water column at the impact point! And because of the high-precision characteristics of centimeter-wave radar, it is even possible to read the error value directly on the radar and input the error value into the fire control system for calibration - in artillery battles between battleships and heavy cruisers, distance and direction finding are not a big problem.

Moreover, after the centimeter-wave radar is connected to the fire control system, the error parameters it reads can be directly input into the fire control system for correction. Compared with the observer on the director relying on the naked eye and experience to judge the distance error, this is undoubtedly much more accurate and convenient! In fact, after the fire control system connected to the radar calculates the change rate of the dispersion range and the maneuvering range of the enemy ship, it can even actively judge the firing time and predict the coverage range for the maneuvering enemy!

Compared with the fire control officers in front of the optical lens who rely entirely on experience to judge the error and the opponent's track, or even rely on eating cod liver oil and taurine to "protect their eyes", this ability can be said to be a revolutionary progress!

In other words, with centimeter-wave radar, ordinary battleships would even be able to fight against Bismarck.

-------

"That is to say, not only can it partially deal with chaff interference, but the previous thing called... covering interference will also not interfere with the British radar because of the different frequencies..."

Listening to Professor Wolff and Zeppelin's awkward explanations, Goering frowned.

"Can our country make this thing now?"

Hearing that the British had something that he didn't, Goering couldn't help but start paying attention to the progress in this area.

"Your Excellency, Imperial Marshal, I'm sorry... Although we have also registered a patent, in fact, the performance of our radar tubes has always been weaker than that of the other party. Their radar has always been much more powerful than ours..."

Seeing that his big boss asked this question, Professor Wolf had no choice but to report with embarrassment and fear.

"I know that the technology investment given by the Air Force in the past is far from enough. I will make additional investments after I return. But I also want to know where our problem lies! Why can't our products achieve their performance?!"

After all, he had been responsible for not paying enough attention to electronic warfare, and Goering frankly admitted his responsibility. But when it came to the fact that Germany's radar was not as good as Britain's, and he had seen with his own eyes "the means that Germany could not crack at present, but Britain might be able to crack", Goering could not help but feel a little angry.

"...This... In addition to theoretical research on magnetrons, the current production process of electron tubes in my country mainly focuses on the cooling and component sealing processes... It is easy to overheat and burn, so it limits the increase in power and the reliability of the equipment..."

Seeing Goering's unhappy face, Professor Wolf, sweating profusely, had no choice but to explain.

Fortunately, Goering knew what was going on, but he still gave Professor Wolff a lecture...

Finally, when it was time to leave, Goering personally gave Professor Wolff an order as he got into the car:

"I will find the funding for the research and development of magnetrons and radar tubes. As for you, I'll give you a chance to make amends! Transfer your expert team to me later and follow Zeppelin to Gibraltar. If the electronic jamming work is not done well, be careful that you will not be able to do this job anymore!"

-

"Other electronic jamming equipment is easy to deal with, but if the British really have centimeter waves and magnetrons, how can I interfere with them? The performance of those two is much stronger than meter waves..." Looking at Goering's car disappearing on the road, Professor Wolff was in tears.

But at this time, Zeppelin and Bismarck appeared together behind Professor Wolff.

"Hey, my dear beast, don't worry, look at what this is."

A slightly teasing female voice sounded behind Wolfe.

Wolfe turned around and found that Bismarck was holding an electronic component: a sealed copper cylinder with a small hollow tube at one end and a transformer-like object at the other end. There were heat sinks machined horizontally on the cylinder, and there were circles of electromagnets on the head and tail of the cylinder. Professor Wolfe could clearly guess that if the cylinder was hollow and there was a light bulb cathode inside, then this was a magnetron!

Well, actually, before Bismarck traveled through time - to be precise, just a few days before she traveled through time, she was watching an electrician repairing the microwave oven at home. She was interested in the principles behind microwave ovens, so she asked a few questions and then listened to the electrician's introduction.

For this purpose, she specifically asked to keep the burnt-out microwave magnetron, and regardless of whether it was dirty or not, she wiped it clean and looked at it over and over again all night.

This magnetron was made according to her memory. Although she didn't know whether the microwave oven magnetron and the radar magnetron were the same thing, she decided to make it first! She happened to hear Zeppelin talking about the problem of centimeter wave electronic interference, so she took out this little gadget and planned to ask Dr. Wolfe to see if it could be used.

Seeing Professor Wolff's eyes begin to light up as he stared at the magnetron prototype in his hand, Bismarck's mood seemed to improve...

Well, the weather is nice today. It seems I should ask the captain for some rewards.

--------

He was indeed the technical director of the German Air Force Radio Department. Professor Wolf's professional level was not to be underestimated. The semi-finished product that Bismarck brought out, which imitated the style of the later magnetron, gave Professor Wolf a lot of inspiration. With the help of the professor's professional calculation and design capabilities, as well as the "repair workshop" of Bismarck and Zeppelin, the accuracy of the processed parts also made a qualitative leap. In just a dozen days, he actually took out several magnetrons!

One with a wavelength of 1.5 cm/frequency of 10000 MHZ, one with a wavelength of 10 cm/frequency of 3000 MHZ, and three with a wavelength of 50 cm/frequency of 600 MHZ. Although they were all hastily made, they are real magnetrons that can be used!

After all, it is a mature product of later generations. The magnets that create the magnetic field are placed at the front and back ends of the magnetron instead of the left and right sides. The heat sink and water cooling tube are opened horizontally on the magnetron body, instead of risking the loss of sealing and power loss, and the troublesome method of vertically drilling holes in the magnetron perfectly avoids several major problems that the German engineers have been unable to solve for a long time:

Tube sealing, power loss, processing time... and more!

Sure enough, sometimes the idea is just a lack of inspiration or something...

In addition, the structure of electronic equipment in this era was still relatively simple. Under the guidance of Professor Wolf, a simple but still usable interference signal transmitter was quickly DIYed - a bunch of basic instruments, a few fuses and an overvoltage protector, plus a frequency modulation control circuit, a diode + capacitor bridge, a DC transformer, a magnetron, several transceiver conversion switches and signal shunt switches. The earliest signal shunt switch was used in the German Lorenz navigation system, although it was a mechanical one...

After adding a "pot" that can adapt to the use of electromagnetic waves in multiple frequency bands... Finally, the FM circuit and the enemy signal receiver of the electronic jammer are connected together...

In this era, this thing is very powerful...

ps: Ahhhh, please give me some razor blades ~ Why are there so few razor blades····

ps: The cheating book guest actually forced the author to ask for a razor blade. I am also drunk. Why is the name of the book called "Blade"... Trash! It's really shameful.

Chapter 380: Sudden Change in the Situation in North Africa

A dozen days later, in mid-April...several people were nervously gathered behind the glass door of a makeshift signal darkroom in the factory, looking at the instruments on the equipment.

"Has the continuous working time reached 24 hours?" The most nervous person was Professor Wolf. After all, it was a temporary DIY thing... Although it would be fine as long as it could transmit a signal with sufficient power and work continuously, he still had no idea...

When he thought about the consequences if the interference failed this time, he was extremely nervous. The Marshal's threat to remove his position was not a big deal. The real problem was whether he could go home if the interference failed...

"Yes...that's right! The time has come! The timing circuit has tripped!" Zeppelin was also sweating. Many things - especially those magnetrons - were made by himself!

Although everyone was puzzled as to why there were such things as "high-power vacuum pumps" and "welding equipment with welding precision comparable to that of top technicians" in the maintenance workshop of the Zeppelin aircraft carrier, fortunately, she still managed to fool these electronic technology experts and aviation technology laymen with her seemingly reasonable but actually nonsense arguments such as "the need to inspect and clean the small pipelines of the aircraft engine and the high-intensity maintenance of the aircraft fuselage"...

Bismarck, standing next to Zeppelin, was also sweating for the same reason. But it seemed that he could breathe a sigh of relief. After 24 hours of continuous testing, there were no sparks or unstable signals. It seemed to be a success...

However, just when the test time was up, the first creature that opened the door of the laboratory and rushed in to check the equipment was surprisingly a small pink rodent...

"Open the door! I'll go take a look!"

"Sister, you guys were having fun here, but you didn't even call me! You're so mean!"

Everyone around was puzzled, looking at the girl who suddenly appeared. However, seeing how close the girl who used to work with them was to her, no one said anything. Could this be another girl with terrifying abilities?

This really makes these grown men feel ashamed. They have already witnessed the technical abilities of these two girls over the past few days, and now another one comes out?

But Bismarck was also surprised.

A hamster actually showed interest and even talent in this kind of thing... Well, Lindmann, who was standing at the back holding his forehead, finally remembered that when Dunkirk was almost bombed by Air Force bombers by mistake, it seemed that it was this hamster that retrieved the communication frequency of the Air Force bombers (which was not reported to them at all)...?

Maybe... this nerdy girl who has absolutely no interest in artillery training might also have her own interests and hobbies?

Lindmann's soul suddenly traveled through half a century and then grasped the essence of later Chinese parents.

Maybe I'm working in the wrong direction? Should I teach her some hobbies or something? After all, this little girl is very biased in her studies.

Just when Lindman was struggling with whether to have quality education, he suddenly remembered that she was a battleship! Why did you study electronics when a battleship should not just fire its own guns?

This is totally a waste of time and talent!

No, we can't go on like this. The prerequisite for Bismarck and Zeppelin to be good at fighting is that they also have superb artillery skills. What can a scumbag like you do...

Lindeman decided to go back and continue to press her down on the bed to recite!

Poor Grape, he was so happy that he had no idea that tragedy was about to happen.

---Don't think of the dividing line as wrong----------

At the same time, there was a dramatic turn in the North African battlefield...

Taking advantage of the "hatred" of the Italian fleet in the Battle of Cape Matapan, a reinforced armored division led by Rommel himself finally successfully reached the Libyan beachhead at the end of March with enough supplies to last for two months. Under the dual influence of the German elite armored division and the supervision team, the usually weak noodles finally came back to life and became hard and stubborn noodles that would rather break than bend.

Under the direct containment of the two Blackshirt Armored Divisions of Litterio and Elliot (their strength was only equivalent to a brigade by German standards) and a large number of Italian Infantry Divisions, as well as the attack of the Foxes that appeared from the flanks, the British frontline troops, which were originally just a group of training grounds, collapsed instantly. They had pushed the Italian army into a state of collapse before, and now they were pushed by the German army again... Well, although they were defeated, they did not collapse into a state of collapse - because after taking down the Warrior Bridge on the Galaza Line, Rommel's supplies and manpower had reached the bottom...

This is really a sad story. As we all know, food and fodder must be sent before troops move forward, and the subsequent supplies must also keep up, so that the front-line troops can fight with peace of mind. If they have nothing to eat or drink and are hungry, the Italians will be the first to disagree!

The fox had no choice but to give up the idea of ​​expanding his victory, stopped miserably, and asked for support.

The culprit behind all this was just four destroyers from a destroyer squadron that Cunningham had urgently deployed to Malta...

Although there were only four of them, they relied on the air force reconnaissance of the Malta base and the absolute advantage of radar in night battles. Except for the lack of radar and the backward sonar model, the Italian light warships, whose weapons, quality and morale were not much worse than those of the British, were actually suppressed by this small destroyer squadron in the night battle...

It's really embarrassing.

Although the British logistics line had to be transported around the Cape of Good Hope, even without the threat of submarines, the entire 1.2-mile voyage meant that most transport ships could only make less than two trips a year. However, even so, with the support of the United States, the British logistics efficiency was still much better than that of the African Corps, which was only a few hundred kilometers from Sicily to Tripoli...

Seeing the British army growing stronger day by day at an obvious speed, but his own supplies were slow to arrive, Rommel, who was extremely anxious, rushed into the telegraph room, and telegrams calling for reinforcements flew to Berlin one after another like snowflakes...

The war situation in North Africa suddenly showed signs of a turning point, but it took a sharp turn for the worse due to lack of logistics, giving Reger the confidence to threaten a breakthrough across the Mediterranean.