PhosphorRTTY vs SimpleFT8

PhosphorRTTY decodes Radio Teletype (RTTY) signals in real time using your iPhone's microphone. Hold your phone near a shortwave radio tuned to an RTTY signal and watch the text appear on screen, character by character, on an authentic phosphor CRT display. No internet connection required. No external hardware. No account. Just your iPhone and a radio. WHAT IT DECODES RTTY is the oldest digital mode in amateur radio — two audio tones representing mark and space, encoding text via the 5-bit ITA2 (Baudot) alphabet or 7-bit ASCII. PhosphorRTTY handles all standard configurations: Baud rates: 45.45, 50, 75, 100 Bd (auto-detected or manual) Shifts: 85, 170, 450, 850 Hz (auto-detected or manual) ITA2 (Baudot) and ASCII modes USB and LSB conventions AUTOMATIC SIGNAL DETECTION The app automatically finds and locks onto RTTY signals: AFC (Automatic Frequency Control) acquires and tracks drifting signals Auto-baud detection identifies the transmission speed Auto-shift detection determines the frequency separation Squelch suppresses noise when no signal is present Or disable any of these and tune manually for full control. FOUR TABS DECODE — The main teleprinter display. Decoded text appears character by character with an authentic mechanical delay. Status bar shows baud rate, shift, mark/space frequencies, and signal lock state. Clear, pause, and session controls. SIGNAL — Live signal analysis. FFT spectrum display (0–4 kHz), scrolling waterfall, mark/space tone indicators, bit period histogram with baud rate markers, and a paper punch tape visualisation of the decoded data stream. LOG — Session history. Every decode session is saved with timestamp, duration, character count, and the full decoded text. Copy, share, or delete individual sessions. CONFIG — All parameters. Audio input gain, decode mode (auto/manual for baud, frequency, and shift), display theme, font size, bell character handling, and RYRY sequence display options. THE DISPLAY Two authentic phosphor CRT themes: Amber (classic teleprinter terminal) Green (military/commercial terminal) Both feature horizontal scanlines, edge vignette, and phosphor glow effects. Monospaced font throughout. RYRY test sequences can be dimmed or hidden to keep the display clean. DSP ENGINE The signal processing is done entirely on-device using a per-sample I/Q quadrature demodulation pipeline: Biquad low-pass filtered I/Q channels for each tone W7AY Automatic Threshold Correction for bit decisions Digital Phase-Locked Loop (DPLL) with per-transition phase correction for timing recovery 512-point FFT for frequency analysis and AFC Asymmetric envelope detection for robust tone tracking through fading Tested against real over-the-air recordings from 20m and 40m amateur bands. Under 1% error rate on clean signals, 4–5% on moderate HF conditions with fixed tuning. WHERE TO FIND RTTY Amateur radio: 14.080–14.099 MHz (20m band), 7.080–7.100 MHz (40m band), 21.080–21.100 MHz (15m band). RTTY contests run throughout the year — during a contest, these frequencies are packed with signals. Maritime and commercial RTTY transmissions can be found across the HF spectrum. A shortwave receiver or SDR with audio output is all you need. REQUIREMENTS iPhone with microphone iOS 17 or later A radio receiver tuned to an RTTY signal (shortwave radio, SDR, or WebSDR audio played through a speaker) No in-app purchases. No subscriptions. No tracking. No network access.

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.