SYNOP reports are typically sent every six hours by Deutscher Wetterdienst on shortwave and low frequency using RTTY.
[2][3] Messages from shipboard weather stations, and in different regions of the world, use variations on this scheme.
This enables Synop, Metar, upperair and satellite data to be processed by a common computer system.
The short wave radio transmission of Synop data was common in the 1980s from Bracknell or Paris but this is now redundant.
Synop data is available as downloadable files from a number of internet sites including the College of DuPage.