Weather satellite pictures (APT)
The analog picture signal that NOAA's older weather satellites sent as they passed overhead. The last one went quiet in August 2025.
ModeWeather satellite pictures
FamilySatellite
Audio example10.0 s
What does it sound like?
Plate 76Satellite
A distinctive 'tick-tock' sound, two ticks per second.
0 Hz1,0002,0003,000 Hz
10.0-second example. Recording: NOAA-19 recording by saphe, Freesound 189860 (CC BY 4.0).
Field marksA steady tick-tock, two per second137 MHzNo longer transmitted since August 2025
Who uses it?
NOAA-15, NOAA-18 and NOAA-19, all now decommissioned (NOAA-18 on June 6, NOAA-19 on August 13 and NOAA-15 on August 19, 2025). Russia's Meteor-M satellites still send pictures near 137 MHz, in a digital format (LRPT).
Where and when can I hear it?
137.1-137.9 MHz. Today you'll hear Meteor-M's digital picture signal there rather than APT; old APT recordings are still widely shared.
What do the decoded parts mean?
- Image: A strip picture of the ground and clouds below the satellite, in visible and infrared light.
Easily confused with
- Satellite telemetry beacon, from the same family