SYNOP (Also called FM-12) is a numerical code used for reporting weather observations. These reports, along with FM-13, i.e. SHIP data, are also transmitted are transmitted in RTTY by the Deutscher Wetterdienst (German Meteorological) at regular times.
It is necessary to click on the fldigi Rv (Reverse) button on the bottom menu bar, lower right corner of the Fldigi screen. That is, the signal must be inverted and the mark and space put at the right place.
The ( mode and frequencies ) in F1B are, in LSB with 50 Bauds:
|147,300 kHz||+/- 42,5 Hertz||DDH 47|
|4583,000 kHz||+/- 225 Hertz||DDK 2|
|7646,000 kHz||+/- 225 Hertz||DDH 7|
|10100,800 kHz||+/- 225 Hertz||DDK 9|
|11039,000 kHz||+/- 225 Hertz||DDH 9|
|14467,300 kHz||+/- 225 Hertz||DDH 8|
A macro key can be setup, if desired, to select the appropriate RTTY parameters. For example, the following macro selects the DDK9 transmission in the 30m band and puts the signal at the 1500Hz “sweetspot” for the FT-991 :-
SYNOP reports look like sequence of words, mostly group of five numbers, such as:
956 SMPO60 LPMG 241200 CCA AAXX 24121 08522 32570 49902 10250 20176 30131 40199 52002 82200 222// 00240 314// 40301 333 82820 83099 555 50004 60005=
Because RTTY code represent letters and numbers with shift code, it might happen that a transmission error unexpectedly shifts numbers to letters. It is possible to turn this behavior off in the RTTY configuration by turning off the “Unshift on Space”, these spaces being the ones between group of words. That way, it keeps the numbers displayed in all circumstances.
Fldigi contains a SYNOP decoder, software which translates these cryptic codes into clear weather reports. When these reports can be associated to a longitude/latitude pair, the report is written in a KML file which can be displayed in Google Earth.
During installation of fldigi, you were prompted to download a couple of data files: These are necessary for decoding many reports.
Much more information available here: SYNOP reports in Fldigi