Decode Radio Teletype (RTTY) signals in real time using your iPhone's microphone. Listen to shortwave radio transmissions and see the text appear on an authentic phosphor CRT display. No internet or external hardware needed.
1.2
October 24, 2026
The first version for iPad. PhosphorRTTY now runs natively on iPad, in every orientation, with larger type and the teleprinter, spectrum, waterfall and punch tape opened out across the full width of the screen. Decoding behaves better on every device. ASCII RTTY now shows the ASCII text alone, PAUSE holds what is decoded and releases it when you resume, DIMMED now dims RYRY sequences, and each saved session records the signal it actually decoded. The LOG screen gains an EXPORT ALL button, the mark and space labels on the spectrum no longer overprint each other, and the status bar now tells you when the microphone is unavailable or interrupted.
MorePhosphorRTTY is a paid utility app for iPhone that decodes Radio Teletype (RTTY) signals in real time using your device's microphone. It displays decoded text on an authentic phosphor CRT screen.
No, PhosphorRTTY does not require an internet connection. It operates entirely on your iPhone, allowing you to decode signals directly from a shortwave radio.
PhosphorRTTY supports standard RTTY configurations including Baud rates from 45.45 to 100 Bd, shifts of 85 to 850 Hz, ITA2 (Baudot) and ASCII modes, and USB/LSB conventions.
Yes, PhosphorRTTY features automatic signal detection, including Automatic Frequency Control (AFC) for drifting signals, auto-baud detection, and auto-shift detection. You can also disable these for manual tuning.
PhosphorRTTY offers two authentic phosphor CRT display themes: Amber and Green, both featuring scanlines, edge vignettes, and phosphor glow effects. You can also customize font size and other display parameters.
PhosphorRTTY has an error rate under 1% on clean signals and 4-5% on moderate HF conditions with fixed tuning. The app uses advanced DSP techniques for robust signal processing.
Yes, PhosphorRTTY offers automatic detection features that make it accessible for beginners. However, manual tuning options provide advanced control for experienced users.
PhosphorRTTY was last updated on March 11, 2026, with version 1.0. Future updates will likely focus on improving decoding performance and adding new features based on user feedback.
