v1.3.0

Full Changelog: v1.2.0...v1.3.0

v1.2.0

If you are upgrading: your sync tuning resets

Settings now live in isobar.ini instead of kgfax.ini. The first time you
run v1.2.0 your existing file is imported automatically — save folder, audio
device, window position, drum speed and sync window all carry over.

The Details… sync tuning does not carry over and goes back to defaults. That
is deliberate. Three of those settings turned out to have been read wrongly by
earlier Isobar versions, so an old file's numbers no longer mean what they say,
and there is no way to tell a file written by an old Isobar from one written by
KG-FAX itself. Rather than silently mis-tune the decoder, v1.2.0 starts clean.
If you had hand-tuned the Details dialog, set it again — the labels now say what
each value actually does.

Your kgfax.ini is never modified, so KG-FAX keeps working alongside Isobar.
.syn files are unaffected and still round-trip both ways.

New

• Recordings load at any sample rate. Previously only 22050 and 44100 Hz
  were accepted, which rejected most SDR recordings outright — HDSDR writes
  12 kHz, others 8 or 48 kHz. Anything from 6000 Hz up now works, resampled
  internally. 44100 Hz still takes its original exact path, so existing decodes
  are bit-for-bit unchanged.
• Details dialog says what it means. The sync settings were renamed from the
  original's cryptic ones (LReSycn, Sync2Thre, SyncWidth…) to
  Release after, Lock after, Max jump, Dark thresh. Two labels were also
  in the wrong places.

Fixed

• Auto ctl was 20× too twitchy. The start/stop tone detector treated its
  setting as milliseconds when it is a count of 100 ms blocks, so it fired after
  0.1 s of tone instead of 2 s. Noise could start or stop a reception.
• Two sync settings were mapped backwards, and a third was treated as a
  pulse width when it actually limits how far the sync position may move between
  lines. Sync tracking now behaves as intended; on a weak off-air recording this
  measured slightly better than before (1713 of 1851 lines locked, none lost).
• The Details dialog silently clamped one setting to a tenth of its valid range.

These came out of a full audit against a settings file generated by the original
KG-FAX, checked line by line against the original program itself.

Which file do I want?

You have	Download
Mac, M1 or later	Isobar-v1.2.0-macOS-AppleSilicon.dmg
Mac, Intel	Isobar-v1.2.0-macOS-Intel.dmg
Windows	Isobar-v1.2.0-windows.zip
Linux, PC	Isobar-v1.2.0-linux-x86_64.AppImage
Raspberry Pi / ARM Linux	Isobar-v1.2.0-linux-aarch64.AppImage

Everything needed is bundled — no FLTK or RtAudio install required.

First run

• macOS — right-click the app → Open the first time. It is ad-hoc
  signed, not notarized, so a double-click will be refused. Needs macOS 15+.
• Linux — chmod +x Isobar-v1.2.0-linux-*.AppImage then run it. Needs
  glibc 2.35+ (Debian 12 / Raspberry Pi OS bookworm and newer).
• Windows — unzip anywhere and run isobar-gui.exe. x64; Windows-on-ARM
  runs it under the system's own emulation.

v1.1.1

If you are on a Mac and downloaded v1.1.0, please download again. That
build silently required macOS 26 (Tahoe) and would not launch on anything
older. This one runs on macOS 15 and later.

A packaging release — nothing in the decoder changed.

New

• Intel Macs have a package again. Two Mac downloads now:
  macOS-AppleSilicon for M1 and later, macOS-Intel for the rest.
• ARM Linux boards, such as the Raspberry Pi: linux-aarch64.AppImage.
  Both AppImages are now built on Ubuntu 22.04, so they also run on older
  distributions — Debian 12 and Raspberry Pi OS bookworm upward.

Fixed

• macOS: the .app required macOS 26. It now needs macOS 15 or later.
  (GitHub's build machines moved to macOS 26 under us, and the build machine's
  version sets the minimum the app will run on.)
• Windows: isobar-gui.exe and isobar-decode.exe showed the generic
  Windows icon in Explorer, and their Properties → Details fields were blank.
  Both now carry the Isobar icon and proper version information.
• Windows: a console window opened behind the app every time it started.
• Building from source failed on older compilers (gcc 11) because of a
  missing #include.

Which file do I want?

You have	Download
Mac, M1 or later	Isobar-v1.1.1-macOS-AppleSilicon.dmg
Mac, Intel	Isobar-v1.1.1-macOS-Intel.dmg
Windows	Isobar-v1.1.1-windows.zip
Linux, PC	Isobar-v1.1.1-linux-x86_64.AppImage
Raspberry Pi or other ARM board	Isobar-v1.1.1-linux-aarch64.AppImage

Nothing needs to be installed alongside these — FLTK and RtAudio are inside
each package.

On macOS the app is ad-hoc signed rather than notarized, so the first time
you open it, right-click the app and choose Open to get past Gatekeeper.
On Linux, chmod +x the AppImage and run it. The Windows .zip is a
portable folder; it also runs on Windows-on-ARM machines through the
system's own x64 emulation.

Full Changelog: v1.1.0...v1.1.1

v1.1.0

Full Changelog: v1.0.2...v1.1.0

v1.0.2

Full Changelog: v1.0.1...v1.0.2

v1.0.1

What's Changed

• CI: self-contained release packages by @skgsara in #1

New Contributors

• @skgsara made their first contribution in #1

Full Changelog: v1.0.0...v1.0.1

v1.0.0

Isobar v1.0.0 — first release

A cross-platform HF weather-fax (WEFAX) decoder, interoperable with KG-FAX v1.1.3. All core receive features are implemented and verified on real JMH recordings; CI builds green on macOS, Linux, and Windows.

Packages

• macOS — Isobar-1.0.0-macOS.dmg (Isobar.app, ad-hoc signed)
• Windows — Isobar-1.0.0-windows.zip
• Linux — Isobar-1.0.0-linux.tar.bz2

⚠️ Known limitation: the prebuilt macOS app needs Homebrew

The .dmg app is dynamically linked against Homebrew's FLTK + RtAudio and is not self-contained — it will only launch on a Mac that has brew install fltk rtaudio installed, and only on Apple Silicon (/opt/homebrew). Intel Macs (/usr/local) are not served by this build.

For now, macOS users should build from source (brew install cmake fltk rtaudio && cmake -B build -S . && cmake --build build) for a working app. A self-contained, properly bundled .app (dylibs embedded via macdylibbundler or static linking) is planned for the next release. The Linux tarball and Windows zip have the same caveat — they expect the system FLTK/RtAudio libraries.

Full changelog: see the commit history. This is the first tagged release.