01
PACTOR
shrike · betaMail sent and received over PACTOR-3
Winlink mail sent and received through WS8EOC over hfmodem’s PACTOR-3. Four messages also received through KB5LZK over PACTOR-1, with a normal session close.
W9SSJ / hfmodem
HF data modem
PACTOR-3 and VARA mail, VarAC chat and file transfers, and HF monitoring. Listen to recorded contacts and inspect the packets, or connect a radio and try the console.
Try WinlinkExperimental prerelease · developers onlyAGPL-3.0-only
Modes
Supported modes
PACTOR-1/2/3 and VARA are beta. ARDOP, Lanner’s RTTY/SITOR-B/NAVTEX modes, voice and CW are alpha. PACTOR-4 and all other modes are experimental. PACTOR-4 protocol and PRNG.
Mode comparison
Carrier placement, timing and mode parameters
01 / shrike · beta · P4 experimental
PACTOR
PACTOR-1, PACTOR-2 and PACTOR-3. Partial experimental PACTOR-4; on-air PACTOR-4 mail transfer is unproven.
02 / kestrel · betaVARA
Winlink mail, VarAC-compatible chat and passive reception at 500, 2300 and 2750 Hz.
03 / besra · alphaARDOP
Winlink mail and passive reception.
04 / sabir · experimentalsabir
OFDM and narrow FSK. The protocol is still changing.
05 / brubru · experimentalRobust Packet
AX.25 packet traffic with KISS, Tracker and AGWPE hosts.
06 / bateleur · experimentalMilitary waveforms, ALE and selcall
MIL-STD and STANAG data modes, ALE scanning and calls, and HF selcall.
07 / lanner · alphaRTTY, SITOR-B and NAVTEX
Passive RTTY, SITOR-B reception and NAVTEX bulletins.
08 / macagua + merlin · alphaVoice and CW
Speech recognition, reply drafts, synthesized voice and Morse contacts. The operator approves each transmitted over.
Results
Observed results
Mail transfers, a BBS download and remotely received beacons. Explore the recordings and evidence.
Evidence
02
VARA
kestrel · betaMail delivery and a VarAC BBS download
Winlink mail received through N5TW and delivered through NS0A. A complete bulletin downloaded from KQ4QWH over BW500, with receive frames up to L11.
03
ARDOP
besra · alphaMail sent and received
hfmodem received messages through WW2MI and W6IDS. An outbound message through WW2MI reached its destination. Codec checks against ardopcf cover all 59 frame types in both directions.
04
sabir
experimentalBeacon decoded at remote receivers
The hfmodem decoder recovered 40 m beacons from recordings at public receivers 103 and 302 miles away. Two transmitted gears decoded at both receivers.
Recorded evidence
Hear the contact. Inspect the packets.
PACTOR-3 mail at SL6, VARA mail at L9, a VarAC BBS download, and ARDOP mail transfers. Each recording states what was received, what was confirmed, and what the replay cannot establish.
Winlink mail
Install hfmodem and exchange email
Send and receive email through a Winlink radio gateway. Use Python 3.13 on macOS or Linux. Connect the FTDX10's USB CAT and audio, or the FT-891's CAT connection and an external audio interface.
Open Terminal and paste this block
python3.13 -m venv ~/hfmodem-env
. ~/hfmodem-env/bin/activate
python3 -m pip install --pre hfmodem
hfmodem winlinkThe first run guides radio, callsign, licence and audio setup, saving configuration only. Grid is optional; press Enter to skip it. Choose PACTOR-3 or VARA HF and a band your antenna is ready for, then a gateway channel. Choose to receive mail or send a text message; sending asks for a recipient, subject and message. Review the final Start this mail call? prompt. Receiving mail is the default; the hidden Winlink password is kept for this session only.
Guided calls set and check Yaesu DATA USB, the data audio route, RTS PTT and saved RF power (initially 20 W). Read the startup summary; the radio settings persist. Set CAT speed to 38400 baud and watch ALC during transmission while adjusting the provisional audio drive.
In each new Terminal, run . ~/hfmodem-env/bin/activate first. Then use hfmodem winlink pactor or hfmodem winlink vara. Add --refresh for a new gateway list. With setup saved, --dry-run previews without opening radio hardware. Ctrl-C stops the call; read its transfer and teardown results. Read saved messages offline with hfmodem winlink --inbox.
VARA chat
Chat with VarAC stations
Use hfmodem's Kestrel modem to hear CQs, call a station and exchange text. Chat is included in 0.4.0.
Terminal / from the checkout root
python3.13 -m venv ~/hfmodem-env
. ~/hfmodem-env/bin/activate
python3 -m pip install -e packages/hfhost -e packages/creance -e packages/hfmodem
hfmodem console setup --transmit
hfmodem console vara chat --band 20 --bw 500 --dry-runSetup saves your radio, callsign, licence and audio settings without transmitting. Reuse your saved Winlink setup if you have one. Choose a band your licence and antenna support.
Review the plan, then start the session:
hfmodem console vara chat --band 20 --bw 500This opens the radio and answers incoming calls. Check the calling frequency and watch ALC during transmission.
- Type
/heard, then/answer Nfor a listed CQ. Or type/cqto call CQ on a checked slot. - Once connected, type text and press Enter.
- Use
/byeto return to monitoring or/quitto exit.
Monitor & call
Monitor signals and make radio contacts
Start a passive decoder at the current dial, or select a frequency or saved peer. You can retune the radio while monitoring.
Terminal / passive reception
hfmodem console pactor monitor
hfmodem console rtty monitor --freq 14080
hfmodem console stanag4285 monitor --mode 1200L
hfmodem console monitor --list-modesFrequencies are USB dial kHz in these examples. Set the radio's sideband and receive filter before starting; a wide 4 kHz voice passband is supported.