AirSleuth Spectrum Analyzer

Nuts About Nets

About this app

AirSleuth turns your Android phone or tablet into a real-time RF spectrum analyzer, using a low-cost RTL-SDR USB dongle connected through a USB-C OTG cable.

Watch the radio spectrum live: a smooth spectrum trace, a scrolling waterfall, and a max-hold overlay reveal what's on the air across your chosen frequency span — broadcast FM and TV, wireless microphones, and other signals within your dongle's tuning range (typically about 24 MHz to 1.7 GHz, depending on your dongle's tuner).

REQUIREMENTS — please read before buying hardware
• An RTL-SDR USB dongle built on the Realtek RTL2832U chipset. These are the common, low-cost software-defined-radio dongles (typically with an R820T2 / R860 tuner). Dongles based on other chipsets are NOT supported.
• A USB-C On-The-Go (OTG) cable or adapter that carries BOTH data and power, so your phone can communicate with and supply power to the dongle. Charge-only cables will not work.
• An Android device that supports USB host (OTG) mode.
• The free "SDR driver" helper app (RTL2832U / rtl_tcp; package marto.rtl_tcp_andro). The first time you press Start, AirSleuth links you straight to it on Google Play — a one-time, one-tap install; afterward it runs invisibly in the background and you never need to open it.

FEATURES
• Live spectrum trace with a clean, de-spurred noise floor.
• Scrolling waterfall, time-aligned to the trace, so you can see how signals change.
• MAX HOLD — the peak level seen at each frequency since the scan began.
• Density (persistence) display that highlights how often energy appears at each frequency.
• Noise-floor reference line.
• Tap-to-place frequency markers (frequency + level read-out).
• Wide-span scanning: AirSleuth stitches many narrow sub-bands into one wide view and filters out the dongle's own spurs, so a broad survey reads cleanly instead of as a forest of spikes.
• Export the current trace to CSV (Shure Wireless Workbench format) and share it.
• Single-screen, landscape, no clutter.

WHO IT'S FOR
RF and wireless engineers, ham radio operators, AV and wireless-microphone technicians, RF educators and students, and anyone curious about what's on the air around them.

PRIVACY
AirSleuth has no accounts, no ads, and collects no personal data. Its only network use is a local loopback connection (127.0.0.1) to the on-device RTL-SDR driver — nothing leaves your device.

Note: AirSleuth is a companion app for RTL-SDR hardware. Without a dongle connected, the full interface is visible but no live data is shown.

Made by Nuts About Nets.

What’s new

First release of AirSleuth — a real-time RF spectrum analyzer and waterfall for RTL-SDR (RTL2832U) dongles connected over USB-C OTG.