From The RadioReference Wiki

Please see the SigIDWiki definition for HFDL for a technical description, software and additional information

A waterfall for HFDL can be found here

Additional Links from the UDXF website


PC-HFDL is a Windows software to decode HFDL data traffic and has been written by Charles Brain. Just feed the HF receiver speaker's output into the soundcard of a Windows PC. It can be downloaded from the HFDL Yahoo group.

PC-HFDL screen

The best monitoring results will be achieved with the following PC-HFDL settings:

  • PREAM ON - to control the audio offset of the receiver
  • SPDU OFF - only needed temporarily ON to see the squitters of a new unknown ground station
  • MPDU ON - see the MPDU packets
  • LPDU ON - see the LPDUs within the MPDUs
  • BDU ON - see the BDUs
  • VERB ON - see more details
  • HFNPDU ON - see the routine position reports
  • HEX OFF - only needed for debugging purposes

So in short, with all options ON except SPDU and HEX, the complete session can be seen: LOG-ON of the aircraft to the ground station giving its 24bit ICAO-ID, the assignment of the 1byte sequence ID number to the given ICAO-ID by the ground station referenced in all subsequent traffic, clear distinction of MPDU packets containing more than just one LPDU, and full traffic details.

The HFDL Yahoo group can be found here. Version 2.042 can be downloaded from this stub page

The .dat file that can be used with the registered version of PC-HFDL can be had by joining the HFDL Yahoo group and requesting one via private mail. It will NOT work with the free version.