These early-model Seetakt systems were followed in 1939 by a modified version known as Dete 1, operating between 71 and 81.5 cm wavelength (368 to 390 MHz) at 8 kW peak and a pulse repetition frequency of 500 Hz. Maximum range against a ship-sized target at sea was up to 22.0 kilometers (13.7 mi) on a good day, though more typically half that. Performance was otherwise similar to the earlier system, with a range accuracy of about 50 m.