Radar in September 1939 was still in the category of black technology, and Germany was leading in this area.

In the original history, Germany also had a certain advantage in the field of radar technology in the early days of World War II, until their opponent Britain invented the multi-cavity resonator magnetron - a microwave emitting device (electron tube), which can greatly increase the power of radar, thereby improving the performance of radar.

However, that was after 1940, and now the British do not have such multi-cavity resonant magnetrons. Dr. Holman (the father of radar in Germany) and GEMA (a radar manufacturer in Germany) have also received the highest priority supply from the Ministry of Armaments and are working hard to develop a multi-cavity magnetron that can be put into practice.

In the era when there was no multi-cavity resonator-type magnetron, it was the German "Freya" radar and the British "local chain" radar that competed. In the autumn of 1937, GEMA developed the "Freya" radar with a detection range of 120 km. At the beginning of 1938, the first batch of improved "Freya" radars were officially installed, which became the most important air defense warning radar in Germany.

And the British "homegrown" chain radar far surpasses the "Freya" radar in terms of detection range, reaching 190 km. However, the long detection range does not necessarily mean that the performance of the radar is superior. Because there is no revolutionary multi-cavity resonant magnetron, the detection range of the British "native chain" radar is achieved by relying on the height of the volume (that is, to be larger). It requires an iron tower nearly 100 meters high to act as an antenna, has no maneuverability at all, and can only detect a sector of airspace in the range of 120 degrees. The Freya radar, on the other hand, is much smaller and can be deployed in a maneuverable manner, and the antenna can also rotate 360 degrees.

Because of its small size, the production and deployment of such radars far exceed those of "local chain" radars. By the outbreak of the war in 1939, at the request of the General Staff, the Luftwaffe had deployed dozens of "Freya" radars in the border areas of western, northern and southern Germany (Austria). Three of them were deployed near the Dutch border in Cleve (the terminus of the Siegfried Line), Lahr and Emden.

All three radars are located very close to the border and can not only effectively cover German airspace, but also detect an area of hundreds of kilometers in the Netherlands. Among them, the radar deployed in Klevard can cover the sky above Amsterdam, the capital of the Netherlands!

The 96 Wellington medium bombers of the 5th British Bomber Group flew over the airspace north of Amsterdam, which was also within the detection range of the Freya radar.

……

"General, at 7:35, a huge number of aircraft were found north of Amsterdam, and they were flying rapidly eastward, and the target was likely to be in our country!"

At 7:45 p.m. German time, at the headquarters of the Luftwaffe 2nd Air Force in Brem, the commander of the 2nd Air Force, Helmut. Lieutenant General Fermier received a report from his chief of staff, Joseph. Colonel Kamhuber heard an unbelievable piece of news.

"What?" Lieutenant General Fermir was stunned, "The radar station can't be mistaken, right?" ”

"Probably not," said Colonel Kamhuber, "the radar station at Clevaud reported to the Air Defense Command at 7:38 a.m., and the radar station at Lahr at 7:41 a.m. similarly reported the discovery of a large number of aircraft coming from Dutch airspace. ”

The establishment of the Luftwaffe in this time and space is different from history, there will be no such strange thing as an air force marine division, and five air defense commands have been established. He was in charge of the northeast, northwest, southeast, southwest, and center of Germany, and was responsible for the air defense of the homeland. When the four major air forces are not transferred out of the defense zone, they are under the jurisdiction of the air force (the Central Air Defense Command is under the direct jurisdiction of the Air Force), and after the air force is transferred, it is under the direct jurisdiction of the Air Force Command.

The radar stations deployed everywhere are "air defense facilities" and are naturally under the jurisdiction of the Air Defense Command. Antiaircraft artillery units and anti-balloon units on the ground are also under the jurisdiction of the Air Defense Command.

In addition, the Air Defense Command will have at its disposal a number of fighter squadrons and reconnaissance aircraft squadrons that will serve as alert missions. When they are not strong enough to deal with the air threat, they call for help from the superior air force or the Air Command.

"A huge number of aircraft ......," Lieutenant General Femmer frowned, "the Dutch? ”

Since relations between the Netherlands and Germany were now very good - and this was due to Wilhelm's restoration - no one would have believed that the Netherlands were going to war with Germany. So the first thing that came to Femir's mind was not an attack by enemy aircraft, but night training of the Dutch Air Force.

"It's unlikely," Colonel Kamhuber, "why do they take off so many planes at night?" ”

"Let's ask the Air Defense Command to make a phone call to verify." Lieutenant General Femmer said.

Because of the good relationship, there was a hotline between the 2nd Air Defense Command and the Air Staff on the Dutch side - a point that the British did not know, and they did not know that the German "Freya" radar could detect the airspace near Amsterdam.

"General, the Air Defense Command is already in contact with the Dutch side," said Colonel Kamhuber, "and they have also dispatched two squadrons of BF-110s, but this number of planes is not enough to intercept them, so they have asked us for reinforcements." ”

If it were daytime, just four squadrons of BF-109s under the 2nd Air Defense Command would have been enough to wipe out the invading British aircraft.

In fact, on September 4, the day after the Scapa Bay raid, the British sent 24 Wellington bombers to bomb the HNA airfield in Wilhelmshaven under the cover of clouds (it was a very cloudy day), only to be detected by radar. Naval aviation dispatched 20 Fokker Zeros and 24 BF-110s to intercept them, shooting down 17 of them.

But it's night, and the BF-109 and Fokker Zero have no night combat capabilities, and the only thing they can use is the BF-110 (the BF-110 is relatively large and can be equipped with a searchlight). However, even the BF-110's ability to search for the enemy at night is very weak, and 24 aircraft in 2 squadrons may not be enough to drive the incoming aircraft back to their hometown.

"Interception? They are suspicious...... The British are violating Dutch airspace? ”

"Yes, the commander of air defense, Lieutenant General Gayle, believes that there is a high probability that these planes will come from the British!"

Lieutenant General Fermier took a breath, "Hell! These damn Brits are trying to pull the Netherlands into the water! ”

He paused, "Call the HNA Command immediately and ask them to take off all of their BF-110s." Let's get our BF-110s up to the sky too, and we'll be sure to stop the damned British! ”

As he spoke, he had already picked up the phone on his desk and was ready to call the Air Force Command.

He already understood what was happening, the British had hit Germany in the heart this time!

As soon as the neutrality of the Netherlands was undermined, Germany's northwestern land frontier would immediately lose its cover. Only about thirty divisions were now stationed on the Siegfried Line, and the German-Dutch border north of Klevaux was virtually undefended.

If the armored forces of the French had come from that direction, both Bremen and Hamburg would have fallen!

……

"Rest assured, leader, not a single British plane will fly over Berlin, our air defense in the north-west is strong, there is a second air force and a naval air force, there are 110 squadrons of BF-8 aircraft alone, and there are radar stations to guide them......"

At 8 o'clock in the evening of September 6, Berlin time, Field Marshal Schleicher telephoned Hitler and reported in the most relaxed tone possible the news of the British plane's flight over Dutch airspace.

Night bombing would cause no serious damage, Berlin was now under night light control, bombers from high above could not see their targets - and Berlin was a very empty city, with a lot of greenery, wide streets, squares and parks. Even if a few planes flew over Berlin, it was unlikely that they would cause relatively large damage.

The real trouble was that the air in the Netherlands became a battlefield!

Hitler, who was carrying a telephone receiver in his hand, also immediately understood what was going on, and he asked in a gloomy tone: "If their army comes from Holland, will we be able to stop it?" ”

"Leader," said Field Marshal Schleicher, "unless the Netherlands and Belgium fall immediately to England and France, it is unlikely that the Anglo-French forces will come over soon." It will take half a month to occupy the Netherlands as soon as possible...... By that time, Poland would definitely be finished. ”

"What if Poland isn't finished?" Hitler asked, "How many troops are there on the Western Front now?" ”

"There were 33 divisions on the Siegfried Line, 11 of which were well armed. The 2nd, 3rd and Naval Air Forces have another 1,000 aircraft to support them. On the southern front we still have 5 divisions to draw from...... If the Italians do not act in hostilities. In Berlin we also had 3 Waffen-SS regiments, 2 paratrooper regiments, 1 Guards Infantry regiment, and a part of Miuta at our disposal, and a brigade of marines in Wilhelmshaven, all of whom were elite. Now it can be transferred to the Western Front for arming.

In addition, we have a lot of reserve divisions that are being trained, and if necessary, we can also send them into battle. ”

Listening to Schleicher's report, Hitler's face became even more gloomy, and the defense of the Western Front was based on the former Siegfried Line. And where the line of defense can't cover it, there is simply no strength to hold it!

He was silent for a long time before he said to Schleicher: "The flight of British bombers over Dutch airspace must be kept secret, as if they were coming from the sea." This may delay for a few days. Also, let's find a way to draw troops from the Eastern Front...... I have to admit that the British played a good card and we are in trouble now! ”

Yes, there was trouble, and it was big!

Because when Hitler gave Schleicher the order, the BF-110 fighters of the Luftwaffe and HNA were too active and had already flown into the airspace west of the Netherlands to block the British bomber group.

Air battles are taking place in the airspace of the Netherlands! (To be continued.) )