Metox radar detector

The R600A Metox, named after its manufacturer, was a pioneering high-frequency radar warning receiver (RWR) used by the German forces on U-boats from 1942–1945.

It was tuned to receive the 1.5-metre (200 MHz) signals used by many British radars of the early and mid-Second World War, notably the ASV Mk.

[2] The radar suffered from problems due to land clutter and inability to determine height, which caused its failure in night fighters but these were no handicap in this new role.

The radar had a fairly crude display but was able to give the range and an approximate direction within an arc either side of the aircraft heading.

Radar cannot detect any reflections returned earlier than half a pulse width so when the U-boat was closer than 9 mi (14 km) the operator would change to the shorter scale.

In December 1942 British code breakers regained the ability to decipher messages encrypted with naval four-rotor Enigma machines and the Germans noticed the resulting increase in U-boat sightings.

Based on their confidence in the Enigma machine, as well as the testimony of a captured British bomber pilot, the Germans came to the erroneous conclusion that the Allies could detect emissions produced by the Metox.

[4] The executive officer of U-230, Captain Herbert Werner said of Metox, "Then, on August 3 [1943], we received a message from Headquarters which had a greater impact on our lives than any since the beginning of the Allied offensive.