Six colour roles per design, per profile: surface, window surface, field interior, text, accent and separator line. A change applies at once in every open window and survives a restart once the settings are saved, like any other preference. Three sources, later wins role by role: the shipped stylesheet from the classpath, then the profile's own stylesheet file if there is one, then the overrides stored in the profile's preferences. resolvePalette is a pure function and reports where every role's colour came from, which the tab shows per field -- with two sources able to decide one colour, that is the only thing keeping "why is this colour what it is" answerable, and the spec calls it mandatory rather than decorative. Four things this had to get right, each learned the hard way and each pinned: A role is a selector and a property, not a property alone. Three of the six are stated outside .root -- text on .label, the separator on .separator *.line -- and -fx-background-color alone appears a dozen times in the evening sheet. Measured: the shipped daylight sheet states no colour at all, the evening sheet states five and implies the sixth. Kst4ContestTheme reads the palette from the store's state and not from remember. That read is what makes a change repaint every open window; remember(darkMode) held the palette until somebody toggled day/evening, so a change reached nothing. A derived colour follows its source's value, never its provenance. The root profile's own stylesheet is the one copyResourceIfRequired writes at every startup -- the shipped sheet itself -- so layer 2 declares the accent on every existing installation with nobody having chosen anything. Keying textAccent on "does this come from a file" repainted the evening accent from green to blue on upgrade and made "reset to shipped" disagree with "discard my changes". The contrast guard measures where colours are actually drawn, read off Theme.kt's Material mapping rather than off the role names: background and surface are both the window surface, and primary is textAccent, not accent. It reports a pair only when it is both under WCAG AA and worse than the shipped sheet -- the shipped sheets have three pairs under 4.5 themselves, so an absolute floor would warn on an untouched client and teach the operator to ignore warnings. The way back out of an unreadable palette is deliberately overbuilt, because it is the one failure that locks itself in. "Reset to the shipped colours" takes the shipped palette as a required parameter and reads no composition local, so there is no path by which it could be drawn in the colours it exists to undo; it looks out of place under a customised palette, and that is what makes it findable. Ctrl+Z, Ctrl+D and Ctrl+R reach the three ways back even with the caret in a colour field. A mistyped colour is refused and the field snaps back. The profile's stylesheet is the hand-editing route the copy under ~/.praktiKST has been promising since it was first written and never read. It is read now. A button writes the shipped template as a starting point and never replaces a file that is already there. An unreadable, truncated or non-CSS file does not prevent startup -- the role falls back to the shipped design. A sheet stating -fx-base and no -fx-background states the derived window surface too, the way JavaFX does, or the most natural hand edit would leave every window the shipped light grey. 101 new tests. All of it runs headless.
KST4Contest
KST4Contest is a Java-based client for the ON4KST chat, developed for coordinated VHF, UHF and microwave contest operation.
The application is developed by Marc Fröhlich (DO5AMF) and since 2026 Philipp Wagner (DN9APW).
Start here
- Project website
- Download Stable, Beta and Nightly builds
- Online manual
- GitHub wiki
- Issues and bug reports
- Development roadmap
What KST4Contest does
KST4Contest combines the ON4KST chat with information that is useful when coordinating contacts during a contest.
Among other things, it can:
- display and filter stations from the supported ON4KST chat categories;
- derive band and frequency information from chat messages and station names;
- maintain Worked and NOT QRV information for the available bands;
- calculate station priorities from distance, activity and other available information;
- manage internal skeds and received Win-Test skeds;
- use AirScout information when evaluating possible aircraft-scatter contacts;
- display stations, paths and additional propagation information on maps;
- exchange information with supported logging programs, Win-Test, PSTRotator and a local DX Cluster interface;
- provide configurable automatic replies for recurring chat requests.
Calculated scores, aircraft-scatter information and path assessments are operating aids. They depend on the available data and should not be treated as guarantees that a contact is possible.
Installation
Ready-to-use packages are available for Windows, Linux and macOS. These packages include the required Java runtime, so a separate Java installation is normally not necessary.
Use the central download page to select the appropriate build:
- Stable is intended for normal contest operation.
- Beta contains changes that are being prepared for a stable release.
- Nightly contains the latest automated development build and is mainly intended for testing.
Documentation
The documentation is available in German and English:
The Markdown sources used for the wiki and the generated PDF manuals are stored in github_docs.
Changes to operating behaviour should be documented together with their purpose and limitations. This is especially important for functions whose result depends on external data, heuristics or information derived from chat messages.
Building from source
Building KST4Contest requires JDK 21. The Gradle Wrapper included in the repository should be used, so a separate Gradle installation is not required.
Linux and macOS:
./gradlew clean build
Windows:
.\gradlew.bat clean build
Repository structure
core/– domain, controller and network code, free of user-interface technologyapp-desktop/– the Compose Multiplatform user interface and the packaging tasksgithub_docs/– German and English manual sourceswebsite/– project website sourcespackaging/– platform-specific packaging files
CI status
Documentation
Builds
License
KST4Contest is distributed under the GNU General Public License v3.0.