SimpleSSTV vs Bandline

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!

Heard a signal you can't identify? Bandline narrows 520 known signals down to a handful — from what you can actually measure. Enter a frequency, hold your phone to the receiver, or match a waterfall shape by eye. Everything works offline, in the field, with no account and no connection. — THREE WAYS IN — BY FREQUENCY Type any frequency and see the full allocation stack: primary and secondary service, national applications, footnotes, licence class and power limits. Then see which known signals actually live in that band, ranked by how commonly they're heard. BY EAR (the interesting one) Hold your phone near the receiver's speaker, or plug in a line-in cable. Bandline records a short sample and measures: - occupied bandwidth (−26 dB) - autocorrelation peaks (ACF, in milliseconds) - tone count and tone spacing for MFSK - estimated symbol rate - burst length, duty cycle, on/off periodicity - modulation class (AM, FM, SSB, PSK, FSK, OFDM-like) Each measurement becomes a filter. The candidate list narrows as you go — 520, then 12, then 3. Drop a chip if a reading looks off. Every measurement shows a confidence indicator, because measuring through a phone mic is honest work but not laboratory work. BY SHAPE Browse a visual grid of reference waterfalls, filtered by band and category. You already know what CODAR and STANAG look like — this is faster than reading a list. — SIGNAL CARDS — Name and aliases, category, active status, frequency ranges, modulation, bandwidth, ACF, symbol rate and mode. A reference waterfall you can pinch-zoom and compare side by side with your own capture on a matched frequency axis. A playable audio sample with a live spectrogram. Protocol notes and links to specifications and decoder software. — ALLOCATIONS — Switzerland, Germany, France, the UK and the USA at launch, from official national tables and the European ECA/EFIS data. IARU amateur band plans included. Auto-detects your region, or set it manually. — BUILT FOR FIELD USE — Fully offline once your library is downloaded. Dark theme with an optional red night mode. Monospace numerics throughout. Density over whitespace — the numbers stay on screen. — WHAT THIS ISN'T — Bandline is an instrument and a reference, not a receiver. It does not connect to SDR hardware; it works alongside whatever radio you already own. It identifies signal types, never message content. No decryption, no descrambling, no guidance on intercepting protected communications — by design, permanently. — PRO — One-time purchase, no subscription, ever. Removes ads, unlocks all offline packs, plus unlimited saved captures, waterfall export and a private custom signal library. Signal reference informed by the community work at sigidwiki.com. Corrections welcome from every card.