Free on the App Store

Your RTL-SDR dongle,
now on iPhone.

Listen to FM broadcasts, aircraft, marine, amateur radio, and weather stations. Connect to any rtl_tcp server and get a GPU-accelerated spectrum analyzer with crystal-clear audio in your pocket.

Download on the App Store How it works
RPi
Mac
Lnx

Works with any rtl_tcp server — Raspberry Pi, macOS, Linux

CoronaSDR app showing live spectrum waterfall on iPhone

A real SDR client, not a toy

Six demodulation modes, GPU-accelerated visuals, and pro-grade controls — designed for iOS from the ground up.

Live Spectrum & Waterfall

Real-time FFT spectrum analyzer and waterfall display rendered with Metal GPU acceleration. Spot transmissions at a glance and drag to tune directly on the display.

6 Demodulation Modes

AM, NFM, WFM, USB, LSB, CW — with squelch, FM de-emphasis (50/75 µs), configurable audio filters, and BFO tuning for SSB.

Scanner

List scan and range scan with configurable dwell, hold, and skip via squelch. Find active frequencies automatically.

Station Memory

Save favorites with custom tags. Import and export your frequency lists via CSV or TSV — share between devices effortlessly.

Background Audio

Keep listening while you use other apps. Full lock screen and Now Playing integration — control playback without opening the app.

Full SDR Control

Gain (auto/manual), PPM correction, direct sampling, offset tuning, bias-tee, and 4 performance profiles from Ultra Low to High sample rate.

Deep Link Automation

Control CoronaSDR from Shortcuts, Safari, or other apps using the coronasdr:// URL scheme.

Live Diagnostics

Monitor throughput (Mbps), IQ/audio buffer health, overrun counters, and network quality indicators in real time.

Up and running in 3 steps

Plug in your RTL-SDR dongle, start the server, and connect from your iPhone. No cloud account, no subscription.

1

Start rtl_tcp on your server

Raspberry Pi, Mac, or any Linux box with an RTL-SDR plugged in:

rtl_tcp -a 0.0.0.0
2

Open CoronaSDR

Enter the server's IP and port, then tap connect. The built-in connection test verifies everything works.

3

Pick a mode and tune in

Try WFM at 100 MHz for your local FM station, or AM at 118–137 MHz for aircraft.

silviu@sdr:~
$ rtl_tcp -a 0.0.0.0
Found 1 device(s):
  0: RTLSDRBlog, Blog V4, SN: 00000001
 
Using device 0: Generic RTL2832U OEM
Found Rafael Micro R828D tuner
RTL-SDR Blog V4 Detected
Tuned to 100000000 Hz.
listening...
Use the device argument 'rtl_tcp=0.0.0.0:1234' in OsmoSDR (gr-osmosdr) source
to receive samples in GRC and control rtl_tcp parameters (frequency, gain, ...).
client accepted! Silvius-iPhone 50930
set direct sampling 0
Disabled direct sampling mode
set offset tuning 1
set bias tee 0
ll+, now 1
ll+, now 2
ll+, now 3
ll-, now 0
ll+, now 1
ll+, now 2
ll+, now 3

Not sure where to start?

Tune to these popular frequencies and discover what's on the air around you.

FM Broadcast
88–108 MHz
WFM — Local radio stations
Aircraft
118–137 MHz
AM — Pilots and ATC communications
2m Ham Radio
144–148 MHz
NFM / USB — Repeaters and simplex
Marine VHF
156.800 MHz
NFM — Channel 16, distress & calling
ISS Downlink
145.800 MHz
NFM — International Space Station
NOAA Weather
162.4–162.55
NFM — Weather radio (US)
70cm Amateur
420–450 MHz
NFM — Ham radio UHF activity
ADS-B
1090 MHz
Aircraft position data

Frequencies vary by region. Check your local band plans for amateur radio and public safety allocations.

Support CoronaSDR

CoronaSDR is free with no ads and no subscriptions. If it's useful to you, consider buying me a coffee to keep development going.

Buy Me a Coffee Donate via PayPal