Echo: Global SDR Receiver

Echo is the ultimate, natively-built iOS client for tuning into remote radio servers. Listen to anything, from anywhere. Dive into international shortwave broadcasts from Asia, monitor aviation communications over the Atlantic, discover mysterious numbers stations, or tune into distant FM stations across the globe, all from your iPhone or iPad.

As featured on RTL-SDR.com: "Designed to make it easy to search for and view public receivers on iOS."

Designed for radio enthusiasts and curious listeners alike, Echo is a powerful aggregator that connects you to over 2,000 community-hosted Software Defined Radio (SDR) receivers and OpenMHz archives. By integrating these reliable streams into a dedicated native environment, Echo delivers true background audio, high-performance mapping, and premium features impossible to achieve with a standard web browser.

KEY FEATURES

Global Interactive Map & Search
Visually browse thousands of remote SDR servers worldwide using our smooth, native MapKit clustering engine, or instantly search 2,000+ receivers by name or location.

Unmatched SDR Compatibility
Seamless support for KiwiSDR, OpenWebRX, WebSDR, and FM-DX Webserver architectures. Want to listen to a private node? Add your own unlisted servers with custom URL entry.

Scanner Mode & OpenMHz
Automatically cycle through station lists at set intervals. Listen directly to public safety, fire, and EMS radio systems via vast OpenMHz archives.

Pro-Level Tuning & Analytics
• Smart Manual Tuner: Instantly tune by entering kHz or MHz; Echo intelligently detects the band format.
• Audio Engine Passthrough: Interfaces directly with server-side signal processors for 100% compatibility with waterfall rendering, plugins, and decoding extensions.
• Intelligent Profile Switching: Automatically switches to the correct server band profile as you tune on supported networks.
• Live Signal Metrics: Real-time SNR (Signal-to-Noise) sorting instantly identifies the strongest receivers in your list.

Offline Frequency Library & Logging
Search an offline, built-in EIBI database of over 11,000 global shortwave and utility frequencies. Save and log your favorite stations to your local device.

Uninterrupted Background Audio
Keep listening when your screen is locked or while using other apps. Our custom audio bridge intercepts complex SDR streams to provide true iOS background playback and lock-screen controls.

Privacy First
Zero tracking. No analytics, no proprietary servers, and no ad IDs. All your logs and favorites are securely stored locally or in your personal, encrypted iCloud container.

Built with speed, aesthetics, and privacy in mind, Echo ensures a fast, premium listening experience. Start exploring the airwaves today!

VoiceOver & Accessibility Support
• Every button, control, and station card announces meaningful context to VoiceOver 
• Scanner controls (play/pause/skip/favorite) are fully labeled and navigable
• Station changes, server connections, and scanner state are announced in real-time 
• Reduce Transparency support: glass effects swap to solid backgrounds when enabled 
• Reduce Motion support: animations are simplified when enabled in iOS settings
• Decorative elements hidden from assistive technology for a cleaner navigation experience