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Install

Download

  1. Open the Releases page.
  2. Under Assets, download CostasApp-win-Setup.exe.
  3. Run it. There is nothing to choose: it installs Costas for your user only (no administrator rights needed), adds it to the Start menu and opens it.

Everything Costas needs is in the installer: the WSJT-X jt9 decoder and Hamlib's rigctld for radio control are bundled. You do not need WSJT-X installed.

Windows SmartScreen

Costas is not code-signed yet, so Windows may show Windows protected your PC with Publisher: Unknown publisher and only a Don't run button. Click More info (under the message), then Run anyway. Edge or Chrome may also say the download "isn't commonly downloaded": choose Keep (in Edge, ⋯ › Keep, then Keep anyway). Each release also has a .sha256 file if you want to check the download. Once releases are signed, the warning names the publisher, and it stops appearing as the signature builds a download history with Microsoft.

Requirements: 64-bit Windows 10 (version 1809) or later, or Windows 11.

Updates

Costas checks GitHub for a newer build when it starts and then once a day. When one is available, a bar appears at the top of the main window:

The update bar

  • Update downloads only what changed since your build (usually a few MB; the bar shows the size), checks it, closes Costas, swaps in the new files and opens Costas again, all within a few seconds. There is nothing to click. It is refused while you are transmitting or in a contact: finish or halt first.
  • Release notes opens the release on GitHub.
  • Skip this version hides the bar until a newer build comes out.

You can turn the daily check off, or check by hand, in Settings › Updates. ☰ › About also has a Check for updates button, which checks even when the daily check is off.

Upgrading keeps your log and settings.

Installed before October 2026?

Builds up to 0.1.0.407 used a different installer, which downloaded the whole program (about 100 MB) on every update. The first update after that downloads the full program once more and moves Costas to the new location below; it removes the old copy and keeps your Start menu entry, log and settings. From then on updates are small. If you had installed for all users (in C:\Program Files\Costas\), remove that old copy yourself from Settings › Apps after the move. An install from before the rename (when the app was called "FT8 Client") is

upgraded too, and its data is moved to the Costas data folder on first start.

Where your data lives

What Where
Log, settings, decode journal, saved audio %LOCALAPPDATA%\Costas\ (for example C:\Users\you\AppData\Local\Costas\)
QRZ API key and password Windows Credential Manager, never in a file
The program %LOCALAPPDATA%\CostasApp\ (%LOCALAPPDATA%\Programs\Costas\ or C:\Program Files\Costas\ for installs from before October 2026)

Uninstalling removes the program but keeps your data folder, so a reinstall picks up where you left off.

Linux (preview)

Each release also has a Linux build, Costas-<version>-linux-x64.tar.gz. It is a receive-only preview: Costas decodes, ranks stations, logs, uploads to QRZ and reports to PSK Reporter, but it does not transmit on Linux yet. Call, Tune and the transmit test say the Linux version is a receive-only preview and the radio is never keyed. Transmit will be turned on once the Linux audio has been checked with a real radio.

  1. Install what Costas uses from your distribution. On Debian and Ubuntu:

    sudo apt install wsjtx libhamlib-utils libportaudio2 libsecret-tools

    wsjtx provides the jt9 decoder, libhamlib-utils provides rigctld for radio control, libportaudio2 is the audio library, and libsecret-tools lets Costas keep your QRZ key in the desktop keyring (without it, the key is asked for again each time Costas starts). 2. For a USB CAT cable, add yourself to the dialout group (sudo usermod -aG dialout $USER), then log out and in. 3. Download the tarball from the Releases page, unpack it and run ./Costas. README.txt inside says how to add it to your desktop's menu.

In Setup's audio step, pick the radio's USB sound card (often USB Audio CODEC). If it is busy because PipeWire or PulseAudio holds it, pick pulse or pipewire and choose the radio's sound card in your desktop's sound settings instead.

Updates: the update bar works the same, but Update opens the release page; download the new tarball and unpack it. It unpacks into a new folder named for its version: run ./Costas from there and delete the old folder. If you added Costas to your desktop's menu, point Exec= in its costas.desktop at the new folder. Your log and settings live in ~/.local/share/Costas/ and are kept.

Next

Start Costas. The first time, it opens Set up Costas.