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 1.3.7

Bug fixes and improved support for new OS releases.
Bug fixes for audio filters and spectrum display.
Added support for the Hermes Lite 2 SDR.

Ratings and Reviews

4.2 out of 5
13 Ratings

13 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!


As a last resort, it works.

I was very apprehensive about buying this, based off the screenshots and the fact that it’s one of the only rtlsdr apps available. $10 is way too much for this. Maybe $2 would be ok but this is sub par. Sometimes it doesn’t connect, or will just decide to drop off and stop all audio and demodulation randomly. The waterfall is glitchy and doesn’t scroll. The interface is very bad. You can’t change modes without stopping the connection and changing it, then starting again, hoping that it will reconnect. You also cannot change the bandwidth of the current frequency. The ui is also glitched on the iPhone 8, the orange text that shows the status is down in the corner and only shows the first letter. As an only option I guess it works, but it really needs big improvements to be worth the $10.

Davidsaintruby ,

Best I have found to date

I know Apple makes it harder to do true hardware. I use SDR sharp and sdr console on pc. This is pretty close on iOS. A little temperamental at times with settings and network server config. But best out there on iOS I have found. Wish it had native air spyserver.


Ronald Nicholson
2.3 MB

Requires iOS 12.4 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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