We’re releasing Spektra, a native macOS spectrum analyzer that turns an inexpensive RTL-SDR USB dongle into a full-featured radio exploration tool. See, identify, and listen to signals from 24 MHz to 1.7 GHz.

The gap it fills

SDR software on the Mac has historically meant running GNURadio in a Linux VM, or using CubicSDR (which hasn’t been updated in years). Spektra is a native Swift/SwiftUI app that bridges directly to librtlsdr — no VMs, no Qt, no X11. Plug in a dongle and you’re looking at the spectrum.

What you can do

Spektra gives you three core capabilities with one device:

  • See signals — real-time FFT spectrum visualization with zoom from 2 MHz wide down to 256 kHz detail, peak detection, and smoothed display
  • Identify signals — automatic classification of 16 signal types based on frequency, bandwidth, and spectral characteristics. Spektra tells you whether you’re looking at an FM station, air traffic control, a weather broadcast, or a pager.
  • Listen to signals — four demodulation modes (FM, AM, USB, LSB) with squelch control and real-time audio metering

16 built-in frequency presets cover the most interesting parts of the spectrum — FM radio, NOAA weather, aircraft ATC, ADS-B, amateur bands, public safety, and more.

The app also includes a 21-activity SDR guide organized by difficulty, covering everything from tuning FM stations to tracking weather satellites and detecting GPS jammers.

Making the invisible visible

Radio signals are everywhere — your neighbor’s baby monitor, aircraft overhead, weather satellites passing over the horizon — but they’re invisible unless you have the right tool. A $30 dongle and Spektra make them tangible.

This fits the same pattern as Tapped (network traffic), Survey (wireless signals), and Harden (security configuration). Each one takes something that’s happening on or around your Mac and makes it visible so you can understand it. Spektra extends that to the radio spectrum.