What is the 'radio wave war' developed by Nazi Germany and Britain during World War II?


Gerard Eviston

During World War II, the Nazi Germany bombed Britain, causing a number of damage. German bombers were able to successfully bombard the target despite night air raids and terrorize the British people. German bombers have succeeded in night air raids using 'radio waves', and 'a fierce battle over the radio waves with the United Kingdom was taking place,' said Eric Brown, a military enthusiast. I summarize it.

England Was Almost Destroyed By Radio Waves – Lessons from History – Medium

During World War II, Germany succeeded in an effective nighttime raid against Britain. In general, it was difficult to detect at night because the target turned off the light, and it was very difficult to achieve results by night bombing with the technology at that time. However, German air bombs bombed at night with very high accuracy.

At that time the UK had a light control in preparation for air raids and night raids were very difficult for the German side, which had neither inductive bombs nor advanced GPS. The RAF also did not have advanced search technology, and during night air raids confirmed the star in the night sky from the transparent dome called Astrodome at the top of the aircraft, and used the sextant to confirm the position of the target It was said that

Of course the accuracy of night air raids using constellations and sextants was not very high, but the German Air Force succeeded in making highly accurate night air raids. The industrial city of Coventry was the target of night air raids by the German Air Force, and the city center was destroyed, causing many deaths. The reason why the German Air Force was proud of its high accuracy in night air raids was that 'radio waves' were used during air raids, says Brown.

Before the war, the German aviation industry spent a large amount of money to build safety systems. Safe landing on the runway is important to ensure the safety of the pilot, especially at night or when visibility is poor, and in Germany the landing navigation system '

Lorentz Beam ' has been developed .

The Lorentz system is a simple system that keeps transmitting two types of radio waves from the ground to the aircraft. To the aircraft flying toward the runway from antennas installed at both ends of the runway, transmit radio waves that can hear a 'dash' signal on the left side from the ground, and radio waves that can hear a 'dot' signal on the right side continue.

When the pilot of the aircraft tunes the radio frequency to a fixed radio wave, the pilot can hear both dots and dashes only in the narrow range where the two radio waves overlap. If the pilot can only hear the dot sound, the aircraft is leaning too far to the left in the direction of travel, so shift the path to the right and look for a position where both the dot sound and the dash sound can be heard. Naturally, in the opposite case it is possible to locate the aircraft in the same way.

Applying this Lorentz system, we thought that Germany could know the exact location of the target. Of course, it is difficult to keep sending radio waves from the attacking point to the plane, but by continuing to send radio waves straight from their territory to the sky above the target, at least the sky above the attacking targets can be reached I can.

The problem is when to drop the bomb, but Germany solved this problem by adding one more signal. The pilot continues to fly according to the first signal and drops bombs at the point where the other signals overlap. If the two signals are illuminated just as they cross the target, the pilot can drop bombs at precise timing even if the ground is dark.

This method, which Germany named

Knickebein , was able to accurately point out the British targets by radio waves transmitted from Nazi's offices throughout Europe.

Soon after, the British side also realized the fact that Germany was using radio waves to enable accurate night air raids, and sent a fake radio wave that appeared to be the German side radio wave, making a jamming operation that misleads a bomber pilot. Implementation. Although the operation succeeded, the Germans improved Knickenbein and devised a new bomber guidance method called

X-Gerät . X-Gerät is a guiding method that was also used for air raids on Coventry.

In X-Gerät, one radio wave leading to the target point and three radio waves crossing are used. The three radio waves are called “Rhine ( Rhine )”, “Oder ( Oder )”, “Elbe ( Elbe )” and are named after the name of the river, Rhine is the target 30 km before, Oder is the target 10 km before the target , Elbe was pointing 5 km before the target. In X-Gerät, the target point is not at the intersection where radio waves overlap but at the end of the intersection. The important point is that the distance between Oder and Elbe (5km) and the distance between Elbe and the target point (5km) are equal. When passing Oder, the special watch of the pilot starts from zero and passes Elbe. The needle turns in the reverse direction. Because the distance between the Oder-Elbe and Elbe-target points is equal, if you drop the bomb when the needle returns to zero again, you can accurately bomb the target point. The system could only be installed on some bombers, so it was operated in such a way that the system-equipped aircraft dropped a flare bomb, which was a marker, and the following aircraft saw it and dropped the bomb.

Since the system installation crashed, the mechanism of X-Gerät was also clarified by the British side. However, it seems that the German army has devised an additional bomber guidance method. It was a system called Y-Gerät , which used a single radio wave to accurately guide a bomber.

In Y-Gerät, radio waves are emitted from the ground to the bomber, and the transponder mounted on the bomber reflects it back to the ground companions. A base station on the ground that received this radio wave calculates the time and direction until the radio wave comes back, and calculates where the bomber is flying and how to reach the destination. After that, it was a mechanism to instruct the pilot by radio and guide to the destination point.

What the United Kingdom used to block Y-Gerät was the radio tower that the British Broadcasting Corporation (BBC) built at Alexandra Palace to broadcast on television. The radio tower had stopped broadcasting from 1939, but fortunately the frequency band used by Y-Gerät and the frequency band used by the BBC coincide, so the UK is faked from Alexandra Palace to Germany I sent a reflected wave to disturb the operation. In addition, BBC's sound engineer was able to detonate the German radio receiver and injure the pilot's tympanic membrane.

Before long, Germany gave up on the bombing of the United Kingdom, and began to use air force to fight the Soviet Union. If Britain did not have the means to counter the German bombardment, the situation could have changed, says Brown.

in Note, Posted by log1h_ik