SDR radio direction finder & VHF receiver with waterfall, map, RTL-SDR support.
About SDR Direction Finder (RTL-SDR)
SDR Direction Finder (RTL-SDR) is a tools app developed by Working with Wildlife.
Download Statistics
SDR Direction Finder (RTL-SDR) has been downloaded 77 times. In the last 30 days, the app was downloaded 30 times.
User Ratings
The app has no ratings yet.
App Information
SDR Direction Finder (RTL-SDR) costs $9.99 to download. The APK download size is 5.27 MB. The latest version available is 4.1. The last update was on June 10, 2026.
Technical Requirements
The app has a content rating of Everyone. The app has been available on Google Play March 2026.
Description
SDR Direction Finder turns your Android phone and an RTL-SDR dongle into a precision VHF telemetry receiver and direction finder, purpose-built for weak signal detection across the full RTL-SDR frequency range with wildlife tracking in mind.
Whether you are a field researcher tracking tagged animals, a falconer monitoring transmitter collars, a ham radio operator hunting hidden transmitters, or an RTL-SDR enthusiast pushing sensitivity limits, SDR Direction Finder delivers narrow-band DSP filtering, a live waterfall display, and a full GPS bearing map in a package that fits in your pocket.
PURPOSE-BUILT SIGNAL PROCESSING
Multiple demodulation modes: CW (default for wildlife tracking), AM, FM, FM-B (wideband FM broadcast with Mono and Stereo options), LSB, USB
Four selectable filter modes deliver real, measurable SNR improvements:
• Wide - general scanning and unknown frequencies • Standard - SNR improvement, real detection range increase for CW/LSB/USB • Narrow - Further SNR improvement for precisely known frequencies • Extreme - Maximum filtering for precisely-tuned CW frequencies
PULSE-COHERENT DETECTION
Coherently combines multiple beacon pulses over time to pull signals out of the noise floor. Calibrate once per beacon, then let the detector integrate 4 to 64 pulses for real SNR gain. SNR and lock status displayed on screen.
BEARING MAP - DIRECTION FINDING ON THE GO
• GPS overlay with live compass cone showing your heading • Log compass bearings from multiple positions with one tap • Automatic intersection calculation estimates the signal source location • POI markers for receiver positions and landmarks • Street, Satellite, and Terrain map tiles • Offline map download for remote fieldwork • KMZ/KML file support for existing survey data • Scale bar, zoom controls, track recording, and screen lock • Import/Export saved bearings, POIs, and tracks to transfer between multiple devices or to open in Google Earth, QGIS, Excel, R, Python or any other tool that handles tabular data.
BIAS-TEE LNA POWER CONTROL
For RTL-SDR V3 and V4 dongles, the built-in software-controlled bias-tee sends 4.5V down the coax to power a masthead LNA directly from the app, with no separate power cable needed.
LIVE WATERFALL DISPLAY
See signals visually even before they’re audible. Pinch-to-zoom spans from ±50 kHz to ±1 MHz. Full-screen landscape mode with live spectrum overlay. Drag-to-tune directly on the waterfall. Choose between Orange and Deep Blue colour schemes.
FIELD-OPTIMISED WORKFLOW
• Frequency presets for each tagged animal • Configurable scan period for hands-free frequency cycling • Physical volume buttons control receiver gain for one-handed field use • Interactive onboarding walkthrough for new users • Sample rate, FFT resolution, and waterfall colour scheme configurable for your hardware and preference
WHAT YOU NEED
• RTL-SDR Blog V3 or V4 dongle • USB OTG cable • Directional Antenna tuned to your tracking frequency • Optional: external wideband LNA for additional sensitivity gain (required for bias-tee power delivery) and/or a Bandpass filter.
IDEAL FOR
• Wildlife tracking or Falconry & VHF telemetry research • Ham radio fox hunting and hidden transmitter direction finding • RTL-SDR enthusiasts pushing weak-signal sensitivity limits • Field researchers needing multi-frequency awareness & bearing logging • Graduate students & NGOs needing affordable telemetry alternatives
No ads. No tracking. No data collection. Developed for Working with Wildlife (workingwithwildlife.org) for conservation and the radio community.
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