# hfmodem

> Open-source PACTOR-3 and VARA compatible waveform generator for developers

- Website: https://hfmodem.ssj.lol
- Category: Other
- Launched on RankRoot: 2026-10-25
- Visitors sent by RankRoot: 0
- Show HN discussion: https://news.ycombinator.com/item?id=50234509

## About

hfmodem is an experimental prerelease software package providing data modem waveforms and protocol implementations for HF radio development. It supports multiple modes including PACTOR, VARA, ARDOP, Robust Packet, STANAG, and text-mode protocols for tasks such as Winlink mail and VarAC-compatible chat. The project includes station control infrastructure for specific Yaesu radio hardware on macOS and Linux.

## Who it's for

Software developers and amateur radio operators working on experimental HF communications.

## Use cases

- Connecting to Winlink mail gateways over PACTOR and VARA
- Participating in VarAC-compatible chat and file transfers
- Passive monitoring and inspecting of HF data packets
- Testing experimental HF waveforms and data modes

## Features

- Implementation of PACTOR-1, PACTOR-2, and PACTOR-3 waveforms and control
- VARA link entry, coded data frames, and session control at 500, 2300, and 2750 Hz
- ARDOP framing, modulation, and link control
- Support for Yaesu FTDX10 and FT-891 radios with native serial CAT and PTT keying
- Passive single-mode receive monitoring and HFLINK console integration

## FAQ

### What does hfmodem do?

hfmodem is an experimental waveform generator and data modem for HF radio applications that implements modes like PACTOR, VARA, ARDOP, and Robust Packet.

### Who is hfmodem for?

It is an experimental prerelease intended strictly for developers.

### Does hfmodem support Winlink mail?

Yes, it supports Winlink mail operations using PACTOR and VARA modes.

### Which radios are supported by hfmodem?

It includes built-in rig profiles for the Yaesu FTDX10 and FT-891, with planned support for X6100 and G90 radios.

### What operating systems are supported?

It runs on macOS and Linux.

### What license does hfmodem use?

It is released under the AGPL-3.0-only license.


Source: https://getrankroot.com/launches/hfmodem. Product facts come from the maker or the product's own website.