Getting started

KlarFunk does not run in a browser tab. The platform holds your licence and serves the download; the app runs locally on your Mac or PC. Five minutes from here to your first coordinated frequency.

1. Download and install

Buy KlarFunk on Gumroad (€49, one-time) and activate the key on your Squaresmile account — that unlocks the download. Signed in, open KlarFunk from the dashboard: without a licence you land on the Activate license page, where you paste the key. Your email must be verified first. New to the platform? The claim page at /claim/klarfunk creates the account and redeems the key in one step. See Licences and paid tools.

Then pick the file for your machine on the KlarFunk page:

Not sure which Mac you have? Apple menu → About This Mac. "Apple M…" means Apple Silicon; "Intel Core" means Intel.

macOS: open the .dmg, drag KlarFunk onto the Applications folder, eject the disk image.

Windows: run the installer, then start KlarFunk from the Start Menu.

Nothing else gets installed. The device drivers and support libraries for every supported device ship inside the app. You do not install Python, and you do not open a terminal to use it.

2. First launch

KlarFunk is not signed with an Apple Developer ID or a Windows code-signing certificate yet, so both systems warn you once.

macOS refuses to open the app the first time. Either of these clears it, once:

• Open System Settings → Privacy & Security, scroll down to Security, click Open Anyway, confirm. Then open KlarFunk again.

• Or paste this into Terminal, press Return, and open the app normally:

  xattr -dr com.apple.quarantine "/Applications/KlarFunk.app"
  

Windows shows a SmartScreen warning when you run the installer. Click More info → Run anyway. If you want to check the download first, its SHA-256 hash is published next to the installer in SHA256SUMS.txt.

The first launch takes a little longer than the rest. On an older Intel Mac it can be 30–40 seconds. A splash screen shows while the scanner engine starts.

3. Plug in your device

Connect your RTL-SDR, tinySA, RF Explorer, HackRF or Airspy before you start the app. KlarFunk detects it automatically; there is nothing to select.

If you plug it in later, click Re-check device in the amber banner at the top. The app tries again without restarting.

4. Your first scan

Click Start scan or press Space. The default sweep covers 470–700 MHz, the wireless-mic band, and a full pass takes a few seconds. Leave it running; each sweep redraws the spectrum.

No device connected? You still get a spectrum. KlarFunk drops into demo mode with a synthetic signal that includes plausible TV transmitters, mic carriers and the LTE edge. The amber banner "Demo mode — synthetic spectrum, no supported device detected" tells you it is not real. No banner means real hardware.

5. Reading the spectrum

• The bright trace is the current sweep; the faint one behind it is the previous sweep.
• The dashed horizontal line is the noise threshold. Anything above it counts as occupied.
• Coloured fills mark what is above the threshold. Once you have registered your own equipment they mean three different things: green is one of your own carriers, amber is something else sitting on a channel you use, red is an unknown signal.
• The Free channels and Occupied ranges cards under the spectrum list the same information as numbers, sorted, ready to read out over a headset.

Type a frequency in MHz into the lookup field to get a free / occupied verdict for that exact spot.

6. Change the language

The interface is available in English, German, French, Spanish, Italian, Dutch and Portuguese. Pick one from the language menu in Settings. The choice is remembered for next launch.

Next

• Turn a scan into usable windows: Find a free frequency window.
• Register the gear you actually carry: Register your equipment.
• Let the Advisor build the whole plan: Coordinate a show with the Frequency Advisor.