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What to listen to · Fax and digital signals
DWD marine weather by RTTY on 4583 kHz: DDH7 after dark
The same German marine bulletins as on 10100.8 kHz, on the lower frequency 4583 kHz under the callsign DDH7: short-range by day, readable across Europe at night, at 50 baud with a 450 Hz shift.
What you hear
The two-tone purr of a 50 baud teletype with a 450 Hz shift, carrying the Hamburg marine weather office's bulletins: synoptic reports from coastal stations and ships, sea-area forecasts for the North Sea and the Baltic, gale warnings, outlooks for the coming days, mostly in German with some English. What the bulletins look like and how the decoding works is in the main article; this entry is the same text on a lower frequency.
Who transmits and why
Deutscher Wetterdienst, callsign DDH7 on 4583 kHz, in parallel with DDK9 on 10100.8 kHz and DDH9 on 11039 kHz. Three frequencies on different bands mean that a ship finds a readable one at any hour and at any distance.
When and where to listen
4583 kHz lives between the 80 and 60 metre amateur bands. In daylight the signal is absorbed and reaches only a few hundred kilometres from northern Germany; from the evening until the morning it carries across Europe, and on long winter nights it is the easiest of the three frequencies to read from far away. In summer the band is noisier at night, with static crashes garbling characters, and 10100.8 kHz may be cleaner.
In ShackDeck
Station catalogue → Fax and digital signals → RTTY DWD 4583 kHz. The program picks a public receiver with the frequency, tunes it, sets the RTTY mode with the station's 50 baud and 450 Hz shift and prints the text line by line in the text panel; nothing of your own is needed. By day open the 10100.8 kHz entry instead.