How accurately did the X-Gerät guide a bomber?

The X-Gerät operated at a much higher frequency than the Knickebein, around 60 MHz. Its equisignal zone was only about 100 yards (91 m) wide at 200 miles (320 km) from the antenna (pending confirmation). The main antenna, Weser, was installed just west of Cherbourg, in France. The crossing signal used a series of three narrow single beams, called Rhine, Oder and Elbe. The official British history describes the system as a main beam or beams laid over the target and crossed by two transverse beams at points separated from each other and from the target by fixed intervals.

In the attack on Birmingham, British analysis found that the vast majority of bombs fell within 100 yards (91 m) of the centre line of the Weser beam (pending confirmation), although spread along the beam over a few hundred yards. HistoryNet states that the equipment could place a bomber within 20 yards (about 18 m) over London (pending confirmation), a figure not found in any other source consulted; the same publication recounts that this conclusion by R. V. Jones seemed, at the time, barely credible.

The experimental unit Kampfgruppe 100 (KGr 100) was tasked with using its X-Gerät equipment to guide other aircraft to the target. Its aircraft attacked first in a small group and dropped flares that the rest could see to bomb visually. The RAF gave the equipment its own code name, "Ruffian".