ALS162 time signal
French longwave time signal radio station
ALS162 is a French longwave time signal and standard-frequency radio station and is used for the dissemination of the Metropolitan French national legal time to the public. TéléDiffusion de France broadcast the ALS162 time signal, provided by LNE-SYRTE and LNE-LTFB time laboratories under ANFR (state body for radio frequencies) responsibility, from the Allouis longwave transmitter at 162 kHz, with a power of 800 kW.
The current time signal is generated by extremely accurate caesium atomic clocks and phase-modulated on the 162 kHz (1850.5707284 m wavelength) carrier signal in a way that is inaudible when listening to the signal using normal Longwave receivers. The ALS162 phase-modulated time signal service requires a more complex receiver than the popular German DCF77 amplitude-modulated time signal service, but the much more powerful transmitter (16 times DCF77's 50 kW) gives it a much greater range of 3,500 km.
The signal transmission is almost continuous, but there is a regularly scheduled interruption for maintenance and tests every Tuesday from 08:00 to 12:00.
The transmitter building contains two caesium atomic clocks which are used to generate the time signal and which are monitored through the SYREF system and GPS common-view measurements, to align with the official French UTC(OP) time scale. The ALS162 time signal exactitude should be in excess of 1 millisecond uncertainty. The monitoring of the ALS162 signal is jointly conducted by LNE-SYRTE, LNE-LTFB and the trade body France Horlogerie and measurement results are published in real time. Monthly monitoring bulletins, like H 649 of the ALS162 signal regarding January 2022 measurements, show if the exactitude goals were met. The time signal is critical for over 300,000 devices (clocks in public places, information panels, traffic lights, public lighting, parking meters, etc.) deployed within French enterprises and state entities, such as French Railways (SNCF), electricity distributor Enedis, airports, hospitals, municipalities, etc. which depend on the signal in France and abroad.
Begin with the source’s own compact description: “ALS162 time signal” is french longwave time signal radio station. The dossier treats that line as a proposition to test through ALS162, time and signal, not as a finished interpretation.
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Maps, plans, fabric surveys and administrative records can establish how the site’s name, extent and function changed over time. The source revision retrieved here is dated May 24, 2026. The linked authority identifier is Q10708146. Authority coordinates are 47.169, 2.205. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1850 and 2022.
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This entry incorporates text from “ALS162 time signal” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.