Morse Listener
Receive only. Point this device's built-in microphone at the speaker and it decodes the tone into text — including the ultrasonic bands you cannot hear. A Bluetooth speaker is fine on the sending side; a Bluetooth headset on this phone is not. Nothing is transmitted and nothing leaves the device.
The microphone is closed. Nothing is being recorded.
Auto watches every band at once and locks onto whichever one is
switching on and off, not whichever is loudest — a steady hum is
louder than a keyed tone and carries nothing. Pin a band if you already know it.
Melody watches the quiet 440 Hz voice hidden
under the house loop — pin this when the sender is playing the
beat; Auto can follow the arp into 1500.
Bluetooth-safe watches only 17 and 19 kHz, which is what
the transmitter sends through a speaker whose codec you cannot see.
Disconnect any headset from this phone: a headset mic drops
capture to 16 kHz and an inaudible carrier cannot exist in the recording.
Waiting for a carrier…
—carrier
—speed
—keying depth
—capture
A message is written down once the channel has gone quiet for a moment, so a half-received word is never logged as if it were the whole thing.
Keep this screen awake and in front. Backgrounding the page or letting the screen lock suspends audio capture on most phones, and a suspended microphone hears nothing.