GQRX and RTL-SDR on Mac OS X El Capitan Quick Start Guide

1 minute read

If you do a Google search for something like “gqrx el capitan”, you’ll find a few guides on using Homebrew to install a bunch of packages that’ll fetch you an old version of GQRX.

It turns out there’s a much easier way with the latest version (2.4.1, at the time of this writing). Just download the app bundle directly from the developer. It’s as simple as an app you drag to /Applications and run.

What is GQRX?

GQRX is a graphical frontend for the GNU Radio SDR (Software-Defined Radio) framework. It allows you to use cheap $20 SDR USB dongles to receive radio frequency signals. I use the extremely popular NooElec NESDR Mini 2 stick.

To see what you can do with GQRX, watch Samy Kamkar’s entertaining Digital Ding Dong Ditch Prank video on YouTube.

Prerequisites

  • A Mac. GQRX also runs on Linux, and I believe, Windows, but the instructions may be different.
  • A supported SDR device, such as the NooElec NESDR Mini 2.

Instructions

  1. Download the GQRX app DMG from http://gqrx.dk/download
  2. Open the DMG and drag the app to /Applications
  3. Plug in your RTLSDR USB device.
  4. Open /Applications/GQRX.app. It will probably give you some warning about an untrusted developer.
  5. Make sure your RTLSDR USB device is selected:
    foo
  6. Test it out by tuning GQRX to a local FM radio station and set Mode under Receiver Options to WFM (Mono). Make sure you hear the station through your Mac’s speakers. foo
  7. For advanced users, your typical rtl-sdr rtl_* command-line utilities are available in /Applications/Gqrx.app/Contents/MacOS/
  8. Tip: As of 2.4, GQRX now includes an explicit zoom control to easily zoom in on a waveform. You can find it in the lower right-hand corner of the Gqrx window under FFT Settings: Zoom

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