Megahertz – See the Airwaves

RTL-SDR analyzer & waterfall

Only for Mac

Free · In‑App Purchases

Mac

Megahertz turns your Mac and an RTL-SDR dongle into a live radio spectrum analyzer. No drivers, no kernel extensions, no command line — plug in a supported receiver and you're watching the airwaves in seconds. A smooth, GPU-accelerated spectrum trace sits above a scrolling waterfall on a shared frequency axis, so you can watch signals appear, drift and fade in real time. Tune anywhere from 24 MHz to 1.7 GHz: FM broadcast, airband, weather satellites, the 433 MHz ISM band, aircraft transponders and everything in between. TUNE YOUR WAY • Type an exact center frequency • Drag or scroll across the display to move along the band • Pinch to zoom into a narrow slice of spectrum • Nudge with the arrow keys — fine steps, or coarse with a modifier held • A Tune menu mirrors every action HUNT SIGNALS • Drop a marker to read its exact frequency, offset and live power • Peak hold catches fleeting transmissions • Burst detection watches a band and freezes the display the moment something appears • Waterfall speed control stretches minutes of activity onto one screen LISTEN (MEGAHERTZ PRO) • Hear the signals you can see: wideband FM, narrowband FM and AM demodulation • Click a signal and listen at the marker — the spectrum and waterfall keep running • Squelch keeps narrowband monitoring quiet between transmissions • Channel-width presets match your target's spacing — 12.5 or 25 kHz FM, 8.33 or 25 kHz airband — and the tuned channel is shaded right on the spectrum RECORD (MEGAHERTZ PRO) • Record what you hear as compact M4A audio files — recordings skip squelched silence, just like a scanner • Capture raw IQ baseband as industry-standard SigMF recordings that any SDR toolchain can open • Retune mid-capture and the recording keeps up, logging every frequency change • Live elapsed time and file size in the status bar, and recordings save wherever you choose • One-time purchase unlocks Listen, Record and aircraft tracking — no subscription TRACK AIRCRAFT (MEGAHERTZ PRO) • Decode ADS-B and Mode S from aircraft overhead on 1090 MHz — callsign, altitude, speed, heading, squawk and position • A live table of everything heard, with the raw frames behind each one • Watch them move across a map, with heading and trail — tiles come from Apple Maps • Or a radar scope, plotted from your receiver — no internet needed • Registration country from the ICAO address, and signal strength per frame • Decoded on your Mac from your own antenna — nothing looked up, no flight database • Anyone can watch the decoder run — counts tick live before you buy ANALYSIS & DISPLAY • Choose the FFT size and window function • Automatic or manual dB range to bring weak signals into view • Several color maps for the waterfall • A live status bar with frequency and power readouts under your cursor • Adjustable sample rate, automatic or manual gain BUILT FOR THE MAC • Quick Look shows any SigMF recording as its waterfall — press Space in the Finder and see the signal before you open anything • Native, GPU-accelerated rendering that stays smooth and easy on the battery • Standard window chrome, an inspector panel, full keyboard and menu control • Dark Mode, VoiceOver and Reduce Motion support throughout • Hot-plug detection with automatic reconnect — and if you own several receivers, Megahertz remembers which one you prefer REQUIRES HARDWARE Megahertz needs an RTL-SDR receiver connected over USB: an RTL2832U dongle with the R820T2 tuner, such as the RTL-SDR Blog V3 or a Nooelec NESDR SMArt. Dongles built on other tuners (including the RTL-SDR Blog V4) aren't supported yet. Megahertz is a receiver only — it cannot transmit on any frequency. Reception of some transmissions may be regulated in your country; always follow local law. Megahertz needs no account and collects no data. Everything is decoded on your Mac from your own antenna — only the ADS-B map's tiles come from Apple Maps. It's built to be the first-class, Mac-native home for software-defined radio.

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Megahertz 1.1 adds aircraft tracking. Tune to 1090 MHz and Megahertz decodes ADS-B and Mode S from aircraft overhead — callsign, altitude, speed, heading and position — in a live table, on a map, or on a radar scope centerd on your receiver. A "Use Current Location" button fills in your receiver position. Aircraft tracking is part of Megahertz Pro; everyone can watch the decoder run live. The map fetches its tiles from Apple Maps. Everything else — including every aircraft position — is decoded on your Mac from your own antenna. Also fixed: a tuner gain bug that was costing about 15 dB across the whole band. Weak signals that were previously buried should now be visible, and audible, everywhere — not just on 1090 MHz.

Version 1.1

The developer, Simon Maddox, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    Simon Maddox
    Size
    3.3 MB
    Category
    Utilities
    Compatibility
    Requires macOS 14.0 or later.
    • Mac
      Requires macOS 14.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    Copyright
    © 2026 Simon Maddox
  • Developer Website
  • Privacy Policy

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