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Difference between revisions of "HFDL"

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==Frequencies in Use==
 
==Frequencies in Use==
*The current version (Sept. 5 2014) of the HFDL database table is 49.
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*The current version (Sept. 5 2014) of the HFDL database table is 49. It's available from the UDXF Modes page [http://www.udxf.nl/HFDL-ACARS-VDL2.pdf here] in PDF.
 
*The .dat file that can be used with the registered version of PC-HFDL can be had by joining the PC-HFDL Yahoo group and requesting one via private mail. It will NOT work with the free version.
 
*The .dat file that can be used with the registered version of PC-HFDL can be had by joining the PC-HFDL Yahoo group and requesting one via private mail. It will NOT work with the free version.
  

Revision as of 18:23, 17 January 2015

What is HFDL?

HFDL is a HF data link protocol, defined in ARINC spec 635-3. The HFDL service is operated by ARINC as GLOBALink service through a worldwide network of HF stations. See this PDF file from the UDXF for more.

The name is somewhat misleading, as HFDL actually describes a class of data signals; it is also referred to as HF ACARS.

  • Transmissions on HF are in USB on a sub carrier of 1440 Hz with a symbol speed of 1800 baud.
  • Modulation is 2-PSK, 4-PSK or 8-PSK with effective bit rates of 300, 600, 1200 or 1800 bits/sec.

PC-HFDL

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 listed below.

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 (which is Vista compatible) can be downloaded from this stub page

Other software that can decode HFDL

Hobby Level Software


Professional Equipment/Software

Frequencies in Use

  • The current version (Sept. 5 2014) of the HFDL database table is 49. It's available from the UDXF Modes page here in PDF.
  • The .dat file that can be used with the registered version of PC-HFDL can be had by joining the PC-HFDL Yahoo group and requesting one via private mail. It will NOT work with the free version.