Supported hardware
Every device KlarFunk speaks to, what each one can and cannot do, band presets, and the devices that need an extra step.
KlarFunk finds the device itself when you plug it in. No Python, no Homebrew, nothing to compile. On macOS there's nothing to install — the RTL-SDR library ships inside the app. On Windows, run 'KlarFunk - Install RTL-SDR Driver' once from the Start menu (the installer puts it there), then plug in and go.
HackRF One, Airspy and SDRplay: Apple Silicon macOS only — hardware-unverified. They go through SoapySDR, which ships only in the Apple Silicon macOS build — the Intel macOS and Windows builds do not include it. Nobody has connected one of these three to KlarFunk yet.
| Device | Connection | Notes |
|---|---|---|
| RTL-SDR Blog V3, Nooelec NESDR, other R820T2 sticks | USB | The reference device, about €40. Supports Listen and the live waterfall. Windows needs the one-time driver step in Getting started. |
| RTL-SDR Blog V4 | USB | Experimental. Not enabled by default and not yet verified on real hardware. |
| tinySA, tinySA Ultra | USB | Sweeps come straight from the analyzer's firmware. No Listen, no live waterfall; the sweep history works. The Ultra reaches 6 GHz, but for anything above 800 MHz its Ultra mode has to be switched on in the device's own menu first. |
| RF Explorer WSUB1G, 3G Combo | USB | Same as tinySA: sweep only. |
| HackRF One | USB | Apple Silicon macOS only — hardware-unverified. Sweep-history strip only, no live waterfall, no Listen. |
| Airspy R2, Mini | USB | Apple Silicon macOS only — hardware-unverified. Sweep-history strip only, no live waterfall, no Listen. The Airspy HF+ is not supported. |
| SDRplay RSP1A, RSP1B, RSPdx | USB | Apple Silicon macOS only — hardware-unverified. Needs the SDRplay API service from SDRplay's own website, installed separately. Sweep-history strip only, no live waterfall, no Listen. |
Bands
Band presets: UHF (470–700 MHz), DECT (1880–1900 MHz) and 2.4 GHz. A preset only offers the part of the band your device can actually reach.
Devices that need one extra step
RTL-SDR on Windows needs the one-time driver step: run KlarFunk - Install RTL-SDR Driver from the Start menu — see Getting started.
SDRplay (Apple Silicon macOS only — hardware-unverified) has a proprietary API whose driver is not bundled. Install the SDRplay API service from SDRplay's own website and make sure it is running before you scan.
tinySA Ultra above 800 MHz needs Ultra mode enabled on the device itself: CONFIG → MORE → ENABLE ULTRA, code 4321. There is no remote command for it, so the app cannot switch it on for you. Readings above 800 MHz are not trustworthy until you have done it.
Intel Macs and Windows: these builds support RTL-SDR, tinySA and RF Explorer. HackRF, Airspy and SDRplay (Apple Silicon macOS only — hardware-unverified) are not available there — SoapySDR ships only in the Apple Silicon macOS build.
Which features need which device
Live waterfall works on RTL-SDR and in demo mode. Every other device gets the sweep-history strip instead — one row per completed sweep, on every device.
| Feature | Works on |
|---|---|
| Sweeping, free windows, the Advisor, every export | Every device, plus demo mode |
| Sweep history strip | Every device |
| Live waterfall | RTL-SDR and demo mode only |
| Listen (FM demodulation) | RTL-SDR only |
If you are buying hardware for this, buy an RTL-SDR Blog V3. It is the cheapest option and the only one that does everything, including Listen. For long sessions, look for the TCXO variant — the standard crystal drifts a few ppm as it warms up, which at 700 MHz is a handful of kHz per carrier over an hour.
Thanks for the feedback.