I SYNOP (surface synoptic observations) sono bollettini, codificati,  che riportano osservazioni meteo provenienti da stazioni automatiche (ogni 6 ore). Sono trasmessi generalmente in HF  (modalità  RTTY) .

Alcune stazioni  che si possono facilmente ricevere sono:  DDK 2 - DDK 7  e DDK 9 del Deutscher Wetterdiens.   Di seguito il  link "schedule radio broadcast" delle stazioni tedesche.

Ecco un esempio parziale di report "registrato " da SeaTTY del bollettino trasmesso da DDK 2 su 4583 KHz :

La decodifica può essere fatta con un piccolo programma DOS: MeteoWare

Questo è l'output (parziale) della decodifica che viene salvato su file txt:

===================================================
72503 32666 62113 10061 21033 30311 40323 56028 91751 333 10061
21005 55 91418=
Day of the month: 14 Observation time: 18 hr
Weather station: 72503 KLGA NEW YORK/LA GUARDIA NY
Latitude: 4046N Longitude: 07354W Elevation: 9 m

Cloud base: 1000 - 1499 m (3334 - 4999 ft).
Horizontal visibility: 16 km.
Total cloud cover: 6/8ths.
Wind direction: 210°.
Wind speed: 13 knots, from anemometer.
Air temperature: 6.1 °C.
Dewpoint temperature: -3.3 °C.
Sea level pressure: 1032.3 hPa.
Pressure change over last 3 hours: -2.8 hPa, decreasing, then steady.
Precipitation amount: 0.0 mm.
Present weather: not significant.
Past weather: not significant.
Maximum temperature: 6.1 °C.
Minimum temperature: -0.5 °C.
===================================================
60020 11580 83307 10189 20129 358 34021 5400) 69912 75022 88800
333 10222 92427=
Day of the month: 14 Observation time: 18 hr
Weather station: 60020 SANTA CRUZ TENERIFE CR
Latitude: 2828N Longitude: 01615W Elevation: 46 m

Cloud base: 600 - 999 m (2000 - 3333 ft).
Horizontal visibility: 30 km.
Total cloud cover: 8/8ths.
Wind direction: 330°.
Wind speed: 7 knots, from anemometer.
Air temperature: 18.9 °C.
Dewpoint temperature: 12.9 °C.
Precipitation amount: 0.1 mm in the last 12 hr.
Present weather: intermittent light drizzle.
Past weather: cloud covering more than half of sky.
Low cloud type: cumulus and stratocumulus (multilevel).
Middle cloud type: no altocumulus, altostratus or nimbostratus.
High cloud type: no cirrus, cirrocumulus or cirrostratus.
Maximum temperature: 22.2 °C.
===================================================
04082 32789 13408 11044 21106 49991 57017 81500 333 11035 21052 553//08 81650 =
Day of the month: 14 Observation time: 18 hr
Weather station: 04082 BIHN HJARDARNES/HORNAFJO IL
Latitude: 6415N Longitude: 01511W Elevation: 10 m

Cloud base: 1500 - 1999 m (5000 - 6666 ft).
Horizontal visibility: > 70 km.
Total cloud cover: 1/8th or less, but not sky clear.
Wind direction: 340°.
Wind speed: 8 knots, from anemometer.
Air temperature: -4.4 °C.
Dewpoint temperature: -10.6 °C.
Sea level pressure: 999.1 hPa.
Pressure change over last 3 hours: -1.7 hPa, decreasing steadily.
Precipitation amount: 0.0 mm.
Present weather: not significant.
Past weather: not significant.
Low cloud type: stratocumulus other than stratocumulus cumulogenitus.
Middle cloud type: no altocumulus, altostratus or nimbostratus.
High cloud type: no cirrus, cirrocumulus or cirrostratus.
Maximum temperature: -3.5 °C.
Minimum temperature: -5.2 °C.