Alexanderson alternator
E75687
continuous-wave transmitter
electromechanical oscillator
high-frequency alternator
radio transmitter
The Alexanderson alternator is an early high-frequency radio transmitter that generated continuous-wave signals using a rotating machine, playing a key role in long-distance wireless communication before vacuum-tube oscillators.
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
continuous-wave transmitter
ⓘ
electromechanical oscillator ⓘ high-frequency alternator ⓘ radio transmitter ⓘ |
| application |
naval communications
ⓘ
point-to-point telegraphy ⓘ |
| developedBy | General Electric ⓘ |
| enabled | reliable transatlantic radio links ⓘ |
| era | early 20th century ⓘ |
| firstUseYear | circa 1906 ⓘ |
| frequencyRange | up to about 100 kHz ⓘ |
| heritageStatus | associated with UNESCO World Heritage Site Grimeton Radio Station ⓘ |
| historicalSignificance |
bridged transition from spark transmitters to vacuum-tube transmitters
ⓘ
first practical source of high-power continuous-wave radio signals ⓘ |
| inventor | Ernst Alexanderson ⓘ |
| keyComponent |
field windings
ⓘ
high-speed rotor ⓘ slip rings ⓘ stator with many poles ⓘ |
| limitation |
large size
ⓘ
limited maximum frequency compared to vacuum tubes ⓘ mechanical complexity ⓘ |
| modulationMethod | on-off keying for Morse code ⓘ |
| namedAfter | Ernst Alexanderson ⓘ |
| notableFrequency | 17.2 kHz ⓘ |
| operatingPrinciple | rotating electrical machine generates radio-frequency alternating current ⓘ |
| powerSource | mechanical rotation ⓘ |
| precededBy | spark-gap transmitter ⓘ |
| preservedAt | Grimeton Radio Station ⓘ |
| replaced | spark-gap transmitter ⓘ |
| requires |
high rotational speed
ⓘ
precise mechanical engineering ⓘ |
| signalGenerationMethod | mechanical alternation of magnetic fields ⓘ |
| status | obsolete for regular communication service ⓘ |
| supersededBy |
vacuum-tube oscillator
ⓘ
vacuum-tube transmitter ⓘ |
| transmissionType | continuous wave ⓘ |
| usedAt | VLF station SAQ Grimeton ⓘ |
| usedBy |
RCA
ⓘ
United States Navy ⓘ early commercial radio stations ⓘ |
| usedFor |
continuous-wave radio transmission
ⓘ
long-distance wireless communication ⓘ transoceanic radio communication ⓘ |
| usedIn |
low frequency radio
ⓘ
very low frequency radio ⓘ |
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
Ernst Alexanderson