HFDL
From The RadioReference Wiki
Overview
HFDL is a HF data link protocol, defined in ARINC spec 635-3.
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.
The HFDL service is operated by ARINC as GLOBALink service through a worldwide network of HF stations.
The PC-HFDL program is a Windows software to decode HF=DL data traffic and has been written by Charles Brain. Besides the commercial version there is an unsupported free version to download. Just feed the HF receiver speaker's output into the soundcard of a Windows PC running PC-HFDL.
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.
Frequencies
| Ground Station | Frequencies in kHz | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | ||
| 01 | San Francisco CA, USA | 21934 | 17919 | 13276 | (11327) | (10081) | 8927 | 6559 | 5508 | 4672 | (2947) | ||||||||||
| 02 | Molokai, HI, HWA | 21937 | 21928 | 17934 | (17919) | (13276) | 11348 | 11312 | 10081 | 8936 | 8912 | 6559 | (5538) | (5529) | (5508) | (5463) | (3434) | (3019) | (3001) | (2947) | (2878) |
| 03 | Reykjavik, ISL | 17985 | 15025 | 11184 | 8977 | 6712 | 5720 | (3900) | (3116) | ||||||||||||
| 04 | Riverhead, NY, USA | (21934) | 21931 | 17934 | (17919) | 13276 | 11315 | 8912 | (6652) | (5523) | 3428 | ||||||||||
| 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, ALS | (21937) | (21928) | (17934) | (17919) | 11354 | (10093) | (10027) | 8936 | (8928) | 6646 | 5544 | (5529) | (4687) | (4654) | (3497) | (3007) | (2992) | (2944) | ||
| 13 | Santa Cruz, BOL | 21997 | (21988) | (21973) | (21946) | (17916) | 13315 | 11318 | 8957 | (6628) | (4660) | (3467) | (2983) | ||||||||
| 14 | Krasnoyarsk, RUS | 13321 | 10087 | (2905) | (2878) | ||||||||||||||||
| 15 | Al Muharraq, BHR | 21982 | 17967 | 13354 | 11312 | 10075 | 8885 | 5544 | (2986) | ||||||||||||
| 16 | Agana, GUM | (17934) | 17919 | 13339 | (13312) | (13276) | 11306 | (11288) | (8936) | 8927 | (8912) | (6661) | (6652) | (6634) | (6550) | ||||||
| 17 | Telde, Gran Canaria, CNR | 21955 | 17928 | (13303) | 11348 | 8948 | 6529 | 5589 | 2905 | ||||||||||||