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HF and LF Modes used by MultiPSK

From The RadioReference Wiki

Welcome to the HF and LF Modes used by MultiPSK page. This article will update a much older one by F1ULT that can be found here. It includes modes that have been since added, and notes those no longer in use. This article will cover modes that can be utilized by MultiPSK found on frequencies below 30 Mhz.


Several modes are used by radio amateurs and these are in bold. However a few are also used by other services. See the notes for additional information. It is important to note that these frequencies can and do vary with the ITU region in which the user resides. Potential users of these modes should check to see which set of frequencies are appropriate for your region.


To get more information on non-ham modes that has been recently reported, you should belong to the Utility DXers Forum (commonly referred to as the UDXF) reflector on groups.io. This group specializes in non broadcast activity (including digital) found below 30 Mhz. The UDXF also has an extensive set of web pages that can be found here.



  • ARQ-E: Obsolete
  • ARQ-E3: Obsolete
  • Coquelet: Obsolete
  • DGPS No longer active in the US
  • MIL-STD-188-110A
    • Note that this mode has been used during Armed Forces Day in the US over the last couple of years. It is used by other countries with heavy encryption
  • PACTOR-1
    • This mode is also used in the maritime industry
  • SITOR-A (aka AMTOR Mode A or AMTOR-ARQ)
    • There are only a small handful of HF maritime stations that use this mode. Most have gone over to PACTOR, using heavy compression and encryption techniques.
    • This mode is also used by the Ministry of Foreign Affairs (MFA) Egypt using the ATU80 alphabet which makes reading this traffic difficult. See this PDF from the UDXF website for a further discussion on this topic
  • STANAG 4285 (listed just as '4285')
    • This mode is usually heavily encrypted which no program can decode; however it can be read when the station sends a test tape in the clear.
    • A listing of STANAG stations from 2020 can be found in the 'Files' section, 'Ute Info' folder of the UDXF reflector. Both text and spreadsheet formats are available
    • Some Notes on STANAG4285 - A DXers View (PDF)