SimpleSSTV

SimpleSSTV is a native iOS app for encoding, decoding, and live-transmitting slow-scan television (SSTV) signals — the method ham radio operators use to share images over audio frequencies.

Slow-scan television converts images to audio tones. Each pixel's brightness becomes a specific frequency between 1500-2300 Hz. Sync pulses at 1200 Hz mark line boundaries. The result is an audio signal you can transmit over any voice-capable radio, or record for later playback.

SSTV has been used by amateur radio operators since the 1950s. It's still actively used today on HF bands, VHF repeaters, and for receiving images from the International Space Station.

ENCODING (Image → Audio)

• Load any image from your photo library, camera, or Files
• Automatic resize and crop to SSTV resolution
• 21 supported modes covering all major SSTV formats
• Real-time encoding with progress visualization
• Play audio directly through speakers for VOX-triggered transmission
• Export to WAV or M4A for later use
• Optional FSK ID and CW ID (Morse code) callsign transmission
• Test pattern generator for signal testing

LIVE CAMERA MODE

• Real-time camera feed with front/back camera switching
• Three trigger modes: Continuous, Motion-triggered, or Periodic interval
• Adjustable motion sensitivity with adaptive background model
• Captures and encodes directly from camera to audio
• Keep the app in the foreground while listening or transmitting

DECODING (Audio → Image)

• Load WAV, M4A, or MP3 audio files containing SSTV signals
• Live microphone capture for real-time SSTV reception
• Automatic mode detection via VIS code identification
• Capture a transmission, then process it to see the decoded image
• FSK callsign detection from received signals
• Precision audio trimming with dual-view waveform editor
• Re-decode saved images with different mode, sync offset, or slant correction
• Handles real-world signal imperfections: timing drift, noise, sample rate variations
• Decode watermark with an automatic stamp or custom Pro text
• Waterfall spectrogram display shows signal frequency over time

SUPPORTED MODES (21 total)

• Martin M1, M2, M3, M4
• Scottie S1, S2, S3, S4, DX, DX2
• Robot 36, Robot 72, Robot BW8
• PD50, PD90, PD120, PD160, PD180, PD240, PD290
• Wraase SC2-180


ISS SSTV EVENTS

• Get notified when the International Space Station transmits SSTV images
• Automatic alerts before and during events, with frequency, mode, and callsign info
• Info card on the decode tab with event details and countdown

FAQ & SETUP TIPS

• Practical advice on audio setup and USB adapters
• Decode quality troubleshooting
• Quick reference for all 21 SSTV modes

IMAGE LIBRARY

• Automatic saving of encoded and decoded images
• Grid view with full preview, metadata, and sharing
• Re-decode any saved image with different settings
• Filter by encoded or decoded

10 LANGUAGES

Available in Arabic, Chinese (Simplified), Dutch, English, French, German, Polish, Portuguese (BR), Spanish, and Turkish — with full right-to-left support.

PRIVACY

No accounts, no analytics, no tracking. Your images and audio stay on your device. Free to encode and decode. Optional one-time Pro purchase unlocks watermark customization and Listening Station Mode. We do not use, sell or share your data for advertising or marketing purposes.

Be aware: Encoded images are audio signals — anyone receiving the audio can decode them!

REQUIREMENTS

• iOS 17.6 or later
• Camera access for live mode
• Microphone access for live decode

Built by a ham radio operator for ham radio operators. 73!