Morse Decoder AI vs PhosphorRTTY

The Morse Decoder AI is an application for decoding Morse code signals using artificial intelligence. The application is designed for use by amateur radio enthusiasts for educational purposes. The Morse decoder listens to the audio stream through the microphone or line input and, upon detecting Morse code signals, decodes them into text. The neural network of the application is trained to decode signals with a speed ranging from 10 to 40 words per minute within a frequency range of 200 Hz to 900 Hz. The application supports two modes of operation: direct (default) and tone filtering mode. In direct mode, the neural network will attempt to decipher Morse code signals in the audio range of 250 Hz to 900 Hz. This mode is suitable for confident reception of Morse code at levels of 7db-9db on the S-meter. The tone filtering mode is ideal for decoding Morse code from noisy weak signals in the presence of radio interference. The audio input signal is first filtered using band-pass filters before being passed to the neural network for decoding. This mode allows for the decoding of faint signals, but it requires the accurate specification of the signal's tone frequency. Each radio amateur selects their own CW tone frequency in the transceiver settings, and it is important to tune precisely to the carrier frequency using the ZIN/SPOT button in YAESU transceivers, or the AUTOTUNE button in ICOM transceivers. There are 3 band-pass filter options available: 25Hz, 50Hz, 150Hz. If you can accurately determine the CW signal tone frequency, using the 25Hz filter, you can decode very faint Morse code signals. The application offers two neural network options: A and B, which can be easily switched in the interface. Network A is recommended for use with stable signal transmission with a constant duration of dots and dashes, while network B is recommended when using a straight key, where the duration of dots and dashes may vary. You have the ability to switch between these networks in real time and observe how each network hears and decodes Morse code. It is important to monitor the level of the incoming audio signal, for which the application provides a sound level indicator. Ensure that the signal is not too quiet or too loud. It is recommended to maintain the signal around -7db, which is sufficient for decoding. Keep in mind that higher audio frequencies are quieter than lower frequencies. Additionally, the application provides various color themes, allowing radio enthusiasts to customize the appearance of the application for comfortable use.

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.