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HFDL

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Revision as of 14:00, 1 March 2011 by Noortvd (talk | contribs) (→‎Other Packages known to support HFDL)

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.

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 Packages known to support HFDL

Frequencies in Use

Thanks to MT Utility World which had the text link. New entries are in bold
ARINC System Table 35

Notes
  • 1 = Panama City - alternate frequency for slot 10 is 21940
  • 2 = Panama City - alternate frequency for slot 6 is 2902
Node ID Xmtr Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
01 San Francisco CA 21934 17919 13276 11327 10081 8927 6559 5508 4672 2947
02 Molokai, HI 21937 21928 17934 17919 13324 13312 13276 11348 11312 10081 8936 8912 6565 6559 5514 5463 4687 3434 3019 2947
03 Reykjavik, ISL 17985 15025 11184 8977 6712 5720 3900 3116
04 Riverhead, NY 21934 21931 17952 17934 17919 13276 11387 11354 11315 10027 8912 8885 8831 6661 6652 6646 5652 5523 3428 3410
05 Auckland, NZL 21949 17916 13351 11327 10084 8921 6535 5583 3404 3016
06 Hat Yai, THA 21949 17928 13270 10066 8825 6535 5655 4687 3470
07 Shannon, IRL 11384 10081 8942 8843 6532 5547 3455 2998
08 Johannesburg, AFS 21949 13321 8834 4681 3016
09 Barrow, AK 21937 21928 17934 17919 11354 10093 10027 8936 8927 6646 5544 5538 5529 4687 4654 3497 3007 2992 2944
11 Panama City PAN 13264 17901 100631
11 Panama City PAN 6589 89842 5589
13 Santa Cruz, BOL 21997 21988 21973 21946 17916 13315 11318 8957 6628 4660 3467 2983
14 Krasnoyarsk, RUS 21990 17912 13321 10087 8886 6596 5622 4679 2905 2878
15 Al Muharraq, BHR 21982 17967 13354 11312 10075 8885 5544 2986
16 Agana, GUM 17919 13312 11306 11288 8927 6652 5451
17 Telde, Gran Canaria, CNR 21955 17928 13303 11348 8948 6529 5589 2905
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