SeaTTY 2.30

SeaTTY 2.30  is an excellent program to receive weather reports, navigational warnings and weather charts transmitted on longwave and shortwave bands in RTTY, NAVTEX and HF-FAX (WEFAX) modes. It can decode GMDSS DSC (HF and VHF) messages. Software also can automatically save NOAA Weather Radio SAME voice messages (NWR SAME) and them digital headers. None additional hardware is required - your need only receiver and computer with a sound card.

Major Features:

1. The working area of the program is divided into several windows, the sizes of which can be changed by the user by dragging the borders.
   
2. In the top window the current spectrum of a signal (blue line) and a peak detector of spectral components (green line) are shown. Ruler under this window shows frequencies of sound spectrum. The long vertical red lines in this window show the working frequencies of the decoder filters. In FAX mode these lines show "black" and "white" frequencies. To change the center frequency, click on the desired frequency (probably between the peaks).
   
3. The bottom window shows an oscillogram of the decoded signal. This window can be hide by the "Setup->View->Show oscillogram window" option
   
4. The "Setup->View->Logarithmic spectrogram scale" option or Alt-Z hotkey switch spectrogram window between linear or logarithmic scale. Analogously, the "Setup->View->Logarithmic oscillogram scale" option or Ctrl-Z hotkey switch oscillogram scale. Logarithmic scale is more convenient usually, but it needs more computer resources.
   
5. The "SQL" button switches squelch on. The number to the left of the "SQL" button determines the squelch threshold. When squelch is switched on, the horizontal red line shows the squelch threshold in spectrogram window.
   
6. The "AFC" button (auto frequency control) adjusts the long red lines (working frequencies) to the closest peak frequencies. The numbers to the left of the AFC button determines the limits of AFC. The first number is local deviation in hertzs, i.e. maximal deviation from current frequency. Second number is global deviation in hertzs, i.e. maximal deviation from last user-selected frequency. User-selected frequencies are shown at spectrogram by short red lines .
   
7. In HF-FAX mode AFC works during phase lines receiving only. These phasing lines are transmitted just before real image transmitting.
   In NWR-SAME and GMDSS DSC VHF modes AFC doesn't work, because frequencies are defined by protocol specifications.
   
8. The "Reverse/Normal" button defines decoded signal polarity. For weather station you should use "Normal" position with USB receiver or "Reverse" position with LSB receiver in RTTY, NAVTEX and FAX modes. Amateur RTTY radio station and some commercial station use opposite polarity. In NWR-SAME mode this option is ignored.
   
9. The "Mode" menu selects a working mode (RTTY, NAVTEX, HF-FAX, NWR-SAME, GMDSS DSC - HF, GMDSS DSC - VHF).
   
10. Signal speed and frequency shift in RTTY mode are selected via the "Speed" and "Shift" menus respectively.
    Weather stations use 50 Baud speed. They use 85 Hz shift in the longwave band and 450 Hz shift in shortwave bands usually. Amateur stations use 45 Baud speed and 170 Hz shift usually. Commercial stations use 50 Baud speed and 170 Hz shift usually.
    
11. The "Shift" menu is used to select normal deviation (800 Hz) or narrow deviation (300 Hz) in HF-FAX mode also. Narrow deviation is used at long wave band.
    
12. The "Setup->Text->Fast synchronization in NAVTEX" menu option define synchronization method in NAVTEX mode.
    When this option is selected, program can synchronize with receiving signal much faster, because it doesn't need special idle symbols to do it. But there is chance to make incorrect synchronization in that case.
    
13. The "OnTop" button puts SeaTTY in front of all windows.
    
14. Received symbols are displayed on the second from top window. The menu option "File->Clear Buffer" clears this window. If the "Setup->Text->Clear Rx window once a day" option is selected, this window is cleared automatically at start of a day.
    
15. The program writes received  symbols in raw log file in the "RAW_LOGS" folder. A name of log file is date-stamped. For example, "01-10-08.TXT" is raw log file for 08 October 2001.If the "Setup->Text->Put time-stamps in raw logs" option is checked, SeaTTY writes receiving time at beginning of each string of a raw log file.
    
16. All weather messages and SAME headers start with "ZCZC" sequence and finish by "NNNN" sequence. SeaTTY finds these sequences in symbol stream and writes messages separately in the "Messages" folder. A name of message file is time-stamped. Four symbols after "ZCZC" sequence is Station ID in NAVTEX mode. Similar message ID is used in RTTY mode also. If station ID is found in a message, it is included in a filename.
    

Enhancements:

• More settings for spectrogram and oscillogram colors were made.
• Options for tuning of auto start / auto stop parameters of FAX mode were made.
  

Requirements:

• Pentium-100 or better, sound card
• Windows 9x/NT/2000/XP/Vista