PhosphorSSTV vs SimpleFT8

PhosphorSSTV decodes Slow Scan Television (SSTV) signals in real time using your iPhone's microphone. SSTV has been the amateur radio image transmission mode since the 1960s. From cold-war era picture transmissions to International Space Station passes, SSTV encodes images as audio tones between 1200–2300Hz. Each scanline is a sweep through frequency space, painting pictures one line at a time across the HF bands. Hold your phone near a shortwave radio tuned to an SSTV signal — or play a recording — and watch the image build scanline by scanline on an authentic phosphor CRT display, just like the original SSTV monitors. No internet connection required. No external hardware. No account. Just your iPhone and a radio. TEN SSTV MODES • Scottie S1, S2, DX — the most widely used SSTV modes on HF worldwide • Martin M1, M2 — popular across European SSTV activity • Robot 36, 72 — YCbCr colour modes, used by the ISS during special events • Robot 8, 12, 24 BW — fast greyscale modes for text, diagrams, and low-bandwidth conditions REAL-TIME DECODING • Progressive scanline rendering — the image builds top to bottom, just like a real SSTV monitor • VIS code detection automatically identifies the transmission mode • Sync-aligned slant correction eliminates timing drift for straight, clean images • Hilbert transform FM discriminator for accurate frequency-to-pixel conversion SIGNAL ANALYSIS • Live FFT spectrum display shows the full 0–4 kHz audio band • Scrolling waterfall reveals the SSTV signal structure in real time • SSTV band markers at 1200 Hz (sync), 1500 Hz (black), and 2300 Hz (white) • Input gain control from 0.1× to 20× IMAGE LOG • Decoded images saved automatically with thumbnails • Full metadata: mode, timestamp, duration, VIS detection status • View full-size, share, or delete • Swipe to delete, tap to view detail AUTHENTIC CRT AESTHETIC • Green and amber phosphor display themes • Scanline overlay, vignette, and glow effects • Monospaced terminal typography throughout • The same retro aesthetic as our PhosphorRTTY and PhosphorCW apps WHERE TO FIND SSTV • 20m band: 14.230 MHz USB — primary worldwide SSTV frequency • 80m band: 3.845 MHz LSB • 40m band: 7.171 MHz LSB • ISS: 145.800 MHz FM during special SSTV events • Or search YouTube/archive.org for SSTV audio recordings to decode PRIVACY PhosphorSSTV makes zero network requests. No accounts, no tracking, no analytics, no ads. Microphone audio is processed entirely on-device and is never recorded or transmitted. See our full privacy policy on our support page. ABOUT SSTV Slow Scan Television was developed in the late 1950s as a way to transmit still images over voice-bandwidth radio channels. Unlike fast-scan television (broadcast TV), SSTV takes seconds to minutes per image, encoding pixel brightness as audio frequency. The 1200 Hz sync pulse marks each line boundary, black is 1500 Hz, and white is 2300 Hz. Every pixel in between is a precise frequency in that range. Amateur radio operators worldwide still use SSTV daily on the HF bands, and the International Space Station periodically transmits commemorative images that can be received with nothing more than a handheld radio.

SimpleFT8 is a native macOS and iOS app for FT8 and FT4, the weak-signal digital modes used by amateur radio operators worldwide. WHAT IS FT8? FT8 is a structured digital mode for ham radio. Stations alternate transmitting and receiving in synchronized 15-second slots, exchanging compact messages over a narrow audio bandwidth. The mode decodes successfully at signal levels well below the noise floor — operators routinely make contacts on a watt or two of power with stations on the other side of the planet. SimpleFT8 puts a real digital station in your pocket. Decode signals using your device's microphone or a USB audio interface and send replies in the next slot. The manual station and local logbook work without an account. WHAT YOU GET • Live decode table per 15-second FT8 or 7.5-second FT4 slot • Slot-aligned transmitter with a structured QSO composer (CQ / reply / report / RR73 / 73) • Tap any decode to start a QSO — the state machine handles the rest of the handshake • Built-in waterfall display with tap-to-set TX frequency • Local QSO logbook with search, editing, ADIF import/export, and complete native backup/restore • Map of stations you've decoded with their Maidenhead grids SIMPLEFT8 FREE Free includes unlimited FT8/FT4 receive, waterfall and decode history; microphone and USB audio; manual CQ, reply and complete QSO exchanges; all TX safety controls; local logging and full portable ADIF import/export; and the basic community map. SIMPLEFT8 PRO — ONE-TIME LIFETIME UNLOCK Pro adds automatic replies, custom-message looping, CAT/PTT rig control, macOS System Audio capture, autonomous band hopping, advanced export scopes, direct QRZ Logbook transfer, and private iCloud log sync. No subscription. Customers who bought SimpleFT8 before it became Free receive Pro automatically. PSK REPORTER + PRESENCE (OPT-IN) If you turn it on in Settings: • Decode reports forwarded to PSK Reporter so you contribute to the global propagation map (rate-limited server-side) • See who heard you in the last 15 minutes, plotted on the map • See other SimpleFT8 operators currently online, on the same map Both toggles are off by default. QRZ transfer and private iCloud log sync are also separately configured and off by default. WHAT MAKES IT DIFFERENT • Native Swift/SwiftUI — no Electron, no Qt port. Looks and feels like a Mac/iOS app should. • Pro System Audio capture on macOS via ScreenCaptureKit — decode straight from SDR software, WebSDR, or any audio your machine is playing, without a virtual cable. • Random caller selection rather than first-come — every station in a pile-up has an equal shot at being picked. • Opinionated QSO state machine handles slot parity, role alternation, and protocol step transitions so you don't have to fight the radio. PRIVACY The app is foreground-only on iOS — the mic stops when the app goes to background. macOS keeps audio I/O alive (long FT8 sessions are the norm). Optional community and logbook integrations are clearly opt-in. No analytics, no tracking, no ads, and no subscription. Built by a ham operator for ham operators. 73 de PD3BAL.