In 1904, Reginald Fessenden contracts General Electric for an alternator capable of generating 100,000 Hz for continuous-wave radio. Swedish-American engineer Ernst Alexanderson designs a series of high-frequency alternators (2 kW to 200 kW) that become the most reliable high-power radio-frequency source for transoceanic radiotelegraphy during and after World War I. The first 1 kW, 50 kHz prototype, delivered in 1906, is what Fessenden uses for his famous Christmas Eve 1906 voice and music broadcast from Brant Rock.