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
• 14 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

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
• 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
• Optional decode watermark stamps mode, timestamp, and callsign on received images
• Waterfall spectrogram display shows signal frequency over time

Note: It's super important to get a clean audio signal into the decoder. There's a new help section in settings with audio setup advice, USB adapter recommendations, and decode troubleshooting.

LIVE CAMERA MODE

• Real-time camera feed with front/back camera switching
• Three trigger modes: Continuous, Motion-triggered, or Periodic interval

SUPPORTED MODES (14 total)

• Martin M1 (114s), Martin M2 (58s)
• Scottie S1 (110s), Scottie S2 (71s), Scottie DX (269s)
• Robot 36 (36s), Robot 72 (72s
• PD50, PD90, PD120, PD160, PD180, PD240, PD290

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 14 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. Buy once, use forever. We do not use, sell or share your data for advertising or marketing purposes.

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

REQUIREMENTS

• iOS 18 or later
• Camera access for live mode
• Microphone access for live decode

This simple, no nonsense utility was built by a ham radio operator for ham radio operators. 73!