Touchstone Mobile

Nuts About Nets

About this app

Touchstone Mobile turns your Android phone or tablet into a real-time RF spectrum analyzer by driving an RF Explorer handheld spectrum analyzer 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, Wi-Fi and other signals within your RF Explorer's tuning range (which depends on the specific RF Explorer model you own).

REQUIREMENTS — please read before buying hardware
• An RF Explorer handheld spectrum analyzer (from Nuts About Nets / RF Explorer). Touchstone communicates with it over a serial-over-USB connection; it does not work without one.
• A USB-C On-The-Go (OTG) cable or adapter that carries BOTH data and power, so your phone can communicate with the RF Explorer. Charge-only cables will not work.
• An Android device that supports USB host (OTG) mode.

No extra driver app is required — Touchstone talks to the RF Explorer directly.

FEATURES
• Live spectrum trace with median smoothing and noise-bias correction for a clean noise floor.
• Two display modes: absolute power (dBm) or signal-to-noise ratio (dB above the 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.
• Automatic peak detection with confidence-coloured annotations and a peak table.
• Noise-floor reference line.
• Tap-to-place frequency markers (frequency + level read-out); tap the trace or the waterfall.
• Wide-span scanning: Touchstone stitches many narrow sub-bands into one wide, seamless view.
• 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
Touchstone Mobile has no accounts, no ads, and collects no personal data. It sends nothing to Nuts About Nets or any third party; it only opens external web links (such as a newsletter sign-up) when you explicitly tap them.

Note: Touchstone Mobile is a companion app for RF Explorer hardware. Without an RF Explorer connected, the full interface is visible but no live data is shown.

Made by Nuts About Nets.

What’s new

First release of Touchstone Mobile — a real-time RF spectrum analyzer and waterfall for RF Explorer devices connected over USB-C OTG.