An RTL-SDR Software Defined Radio receiver app for iOS devices.  Listen to AM, FM, SSB and CW radio signals. View an RF spectrum and waterfall. Connect, via the rtl_tcp network protocol, to a networked RTL-SDR USB peripheral.

This app requires an external rtl_tcp server. iOS devices do not currently support the direct connection of USB peripherals such as an RTL-SDR. Thus, the use of this app requires network access to a server, such as a Raspberry Pi (or Mac), with an RTL-SDR unit plugged into its USB port, and running the rtl_tcp protocol at an TCP/IP network address accessible from your iOS device. This allows a Raspberry Pi (or Mac) to act, essentially, as the USB port adapter for your iOS device. (This app can also connect to hfp_tcp for the Airspy HF+, rsp_tcp for SDRPlay devices, and lmm_tcp for the LimeSDR Mini; see GitHub for source code.)

No support is provided for installing any of the rtl_tcp or other tcp software needed to use this app (with a Raspberry Pi, or otherwise). Please do not download this app unless you are already familiar with Software Defined Radio, have an RTL-SDR or equivalent USB SDR peripheral, and have already installed and tested rtl_tcp on your Raspberry Pi, Mac, or other server. Note that this app requires a very high bandwidth network connection in order to receive streams of real-time RF samples from an RTL-SDR. It is recommended that your rtl_tcp server be on a wired connection rather than on the same WiFi as your iOS device.

What’s New

Version 1.3.2

- Bug fixes and improvements to audio and CW filters
- Added support for lower Airspy HF+ and HF+ Discovery sample rates

Ratings and Reviews

4.0 out of 5
9 Ratings

9 Ratings

GweepDad ,

This app is long overdue; Basic features but a good effort. Thanks!

Looking forward to using this app as it matures. It worked right away with my Raspberry Pi RTL server. It even works OK over my VPN.

Features that it definitely needs in future updates:
1) The upconverter frequency needs to allow a more exact calibration down to 1 Hz.
2) Same for the PPM value. At least 3 decimal points are needed for accuracy.
3) A slider would be helpful for fine tuning SSB and CW signals. Say +/-1000 Hz. Maybe along a vertical edge.

Nice effort, well done. Keep up the good work. Much appreciated!

Flintstone, Fred ,

Works great

The BIG variable is network bandwidth. But at the lowest sampling rate it works good. Using a Raspberry Pi 3+ server.

Up/Down tuning buttons would be nice with it changing the selected frequency digit for slow or fast tuning.

KD0 ,

Could use some polish...

This is the ONLY (iOS) RTL-SDR application in town. It’s get the job down, albeit crashes occasionally and could use some polish. I’d like to be about to pinch bandwidth. Needs a LOT of work. I sincerely hope they continue developing. Could be a great app. Not worth $10, I hate to say..


Ronald Nicholson
9.6 MB

Requires iOS 12.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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