The Fritz-X guided bomb was based on the PC 1400 bomb (Panzersprengbombe, Cylindrisch 1,400 kg), a bomb specially designed against armoured targets such as battleships or cruisers. The development had its beginning after the difficulty shown by the German pilots in attacking moving ships during their participation in the Spanish Civil War. It can be said that it is one of the first missiles to enter service, and also that it was the first to sink a ship in combat.The core of the Fritz-X bomb was the Kehl-Strasbourg radio control link device, which was also installed on the rocket-boosted Henschel Hs-293 anti-ship glide bomb. This system was composed by the Funkgerät (FuG 203) Kehl radio-control transmitter and the Funkgerät (FuG 230) Strasburg receiver. The transmitter worked on the 48.2 MHz to 49.9 MHz low-VHF band radio frecuency. They had a maximum range of about 6 km and 18 different command frequencies could be selected.The Allies produced different jamming devices to disable the receiver installed in the tail of the bomb. United States developed the XCJ series from September 1943 and UK developed the Type 650 transmitter early in 1944. This was a very successful model that was able to disable the bomb receiver regardless of its command frequency. Germans developed a “counter countermeasures” system consisting of a wired remote control system. This device was composed by an S207 audio amplifier installed in the bomber, and an E237 audio receiver that was installed in the bomb. This system had a maximum range of 12 km and was built by Stasfurter Rundfunk GmbH.The bomber released the Fritz-X and immediately reduced its speed to allow the bombardier to see where bomb was. Then, he was able to drive it towards the target with the help of a flare installed in the tail of the bomb. The bombardier kept track of the bomb with the aid of a conventional Lotfe 7 bombsight. This bomb used to be released at about 5,500 meters and about 5 km from the target, then, the bomber must remain in the area flying at low speed and steady course to have the bomb in sight. The bomb reached more than 1,000 km/h and was capable of penetrate up to 130mm of armour.On September 9, 1943, six Do-217 K2s bomber from Gruppe III of Kampfgeschwader 100 “Wiking” with one bomb each, attacked the Italian Rome and Italy battleships. They sunk the first and seriously damaged the second when they went to Tunisia after the armistice. Accuracy of these bombs depended entirely on the bombardiers, but they were really succesful. Usually, any bombardier “placed” the bombs at 15 meters from the target 50% of the time, or at 30 meters in 90% of the launches.It is estimated that some 600 Fritz-X were built at a rate of 65 per month and although the weapon was relatively effective, its withdrawal was due to the high number of launcher bombers that were shot down during its use. In addition to the Italian Rome and Italy battleships, the British HMS Warspite was also damaged on September 16, 1943 near Salerno and other smaller units also received the attention of these guided bombs, authentic precursors of the current laser bombs.
