Unternehmen Cerberus
Although GCI began to supplant CHL during 1941 and especially 1942, CHL continued to provide an important early warning role. In February 1942 the Germans mounted the Channel Dash, moving two of their battleships to harbors in Germany by sailing them right up the English Channel. This major embarrassment was due largely to supremely effective jamming on the part of the Germans, who managed to render the CH and CHL radars covering the coast entirely ineffective without the operators even noticing.