How Radio-Controlled Bombs Were Jammed

The following article was printed in the December 1945 issue of C.I.C. (Combat Information Center) published by the U.S. Office of the Chief of Naval Operations.

How Radio-Controlled Bombs Were Jammed

The long, violent history of this war saw the rise of many new or radically improved weapons, from the magnetic mine in the early days to the “personnel-controlled bomb” (suicide plane) of recent fame. The story of Allied countermeasures to the threat of Axis weapons is in many cases as dramatic as the weapons themselves.

Henschel Hs 293 Missile

German planes carried the radio-guided missiles under their wings.

For instance, take the case of the German radio-controlled bomb. As early as 1941 British Intelligence began receiving reports that the Germans were developing a bomb which could be remotely controlled from a parent aircraft. Development and operational use, however, are two different things, and it was not until August, 1943, that the Luftwaffe was ready to unveil it. A group of corvettes on anti-submarine patrol in the Bay of Biscay were attacked by what was identified as a remotely controlled bomb—a missile resembling a small fighter plane—capable of radical maneuvering both in azimuth and elevation. The parent aircraft were DO217 twin-engined bombers. One of the corvettes was sunk, another damaged. Later in August further highly successful attacks were made against shipping in the Mediterranean and Bay of Biscay. The bomb (designated HS293) was released by the parent plane at altitudes of 3000-5000 feet and ranges of three to five miles from the target. The missile was jet-assisted shortly after its release; its speed, variously estimated at the time, is now known to have been about 325 knots. The controlling operator in the plane was able to follow the bomb visually by observing a light in the tail.

During and immediately following the Salerno landings the German guided missile program moved into high gear. The enemy introduced another type of controlled missile, the FX, a radio-corrected 4400 pound bomb of tremendous power and accuracy, as anyone present in Salerno Gulf at that time will testify. The Luftwaffe caught units of the Italian Fleet racing to reach Allied ports and scored heavily with both HS293 and FX bombs. They attacked Allied shipping in Salerno Gulf, sinking and damaging several British and United States warships, large and small. It was estimated that nearly 50% of the bombs launched were hits or damaging near misses.

At that time radio control was suspected (on the basis of prisoner-of-war reports) but was by no means confirmed. The control hand was supposed to lie in the 20 Mc region, and desperate, hastily improvised jamming effort was concentrated in this band, which seemed to improve morale without affecting the accuracy of the missiles.

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