Utilities Windows
JS8Call
Send keyboard-to-keyboard messages over HF amateur radio with JS8Call, a free, open-source Windows application with station discovery, message relaying and store-and-forward messaging.
- Operating system
- Windows 10 and Windows 11
- Architecture
- x86_64 (64-bit)
- Download package
- EXE installer
Requires an HF radio station with suitable audio connections and configuration. This entry selects the publisher's Windows x86_64 package, not its separate Linux or macOS builds.
Link checked · Download guidance
What is JS8Call?
JS8Call turns an HF radio station into a text-messaging station using the weak-signal JS8 mode. It is aimed at amateur radio operators who want free-form conversations, directed messages and stored messages rather than the short exchanges of conventional FT8. The interface brings together decoded band activity, a callsign list, message composition and a waterfall showing signals in the audio passband.
Heartbeats help discover stations, while directed messages and relaying provide ways to pass traffic beyond a single conversation. These are radio functions, not an internet chat service: you need a suitable HF transceiver, working audio connections and station configuration. Accurate timing and calibrated audio levels matter for decoding and transmitting.
This entry links to the publisher-listed JS8Call 3.0.3 Windows x86_64 EXE installer. The publisher lists Windows 10 and 11; the download catalog dates this release July 12, 2026. JS8Call-Improved was the temporary application name for version 2.4.0; from 2.5.0 the application is again called JS8Call, while the development organization retains the JS8Call-Improved name. The screenshot is the publisher's older 2.4.0 interface illustration, not a capture or test of the linked 3.0.3 build.
What it offers
- Exchange free-form keyboard-to-keyboard messages using the JS8 weak-signal radio mode.
- Send directed messages, relay traffic and use stored-message workflows.
- Discover active stations through heartbeats and monitor callsign activity.
- View decoded band activity alongside a waterfall and message composition pane.
- Use group messaging and configurable message templates.
Good to know
- Not a standalone internet messenger: on-air operation requires a suitable HF radio station, audio setup and configuration.
- Clock synchronization and audio calibration affect decoding and transmission; installing the program alone does not establish a working station.
- JS8 messages are not interchangeable with WSJT-X FT8 messages despite the shared technical heritage.
- The publisher-hosted screenshot shows an older 2.4.0 interface; it does not establish the appearance of version 3.0.3.
Product images
Sources
References used for this listing. Retrieval dates do not indicate hands-on testing.
- JS8Call-Improved — Modern HF Digital Communication ↗Retrieved
- JS8Call — Downloads and project-name clarification ↗Retrieved
- JS8Call-improved official repository — README and licensing ↗Retrieved
- JS8Call-Improved: JS8Call_User_Guide — development guide, stable operating prerequisites only ↗Retrieved
- Softonic discovery source — protected page, no product facts extracted ↗Retrieved
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