F4IOZOlivier · radio amateur · JN18FS

Which mode? by ear and on the waterfall

A few seconds of signal and its waterfall scrolling by: CW, FT8, RTTY, SSTV, packet… which one is it? String right answers together: the multiplier climbs. All games

Lend an ear!

The game makes sound: turn the volume up. Choose the level, the noise and the mode beside, then go. Keys 1 to 6 to answer, Enter for what comes next.

Badges

Good earA first right answer.
First beepA right answer in under 2 seconds.
Combo ×4Reach the ×4 multiplier.
Perfect pitchTen right answers in a row.
Through the hiss10 right answers with noise on.
Heard them allRecognise each of the game's modes at least once.
Clean copyFifteen right answers out of fifteen.
Express sweep15 right answers in a timed game.
Human decoder12 right answers or more in a Hard game.
All-rounderFinish a game of each game.

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Telling a mode

On a receiver set to USB, each mode has its own voice and its own trace on the waterfall (time runs down, frequency goes left to right, the colour tells the strength).

CW a carrier keyed in dots and dashes: Morse.
SSB (voice) the voice, without carrier, about 2.7 kHz wide: a hiss that talks.
FM and 1750 Hz the hiss goes quiet as the carrier comes, the 1750 Hz tone opens a repeater (in Europe), the closing “kchh”.
SSTV the VIS header (1900 Hz, then the mode's code), then each line and its 1200 Hz sync; the picture between 1500 and 2300 Hz.
Packet, APRS (AFSK 1200) 1200 baud, two tones at 1200 and 2200 Hz (Bell 202): a crackling burst.
RTTY 45.45 baud, two tones 170 Hz apart (mark and space), the Baudot code: the teleprinters' warble.
FT8 8 tones 6.25 Hz apart, 0.16 s per symbol, 15-second cycles: little tunes all at once.
WSPR 4 tones 1.46 Hz apart, 0.68 s per symbol, almost a pure line; a transmission lasts nearly 2 minutes.
PSK31 a carrier whose phase flips, 31.25 baud: a steady warble, a narrow trace.
FT4 4 tones 20.8 Hz apart, 48 ms per symbol, 7.5-second cycles: FT8 in a hurry.

Good to know The game's sounds are made here, on each mode's pattern, not recorded: a decoder would read nothing in them. FT8 only plays a few seconds of a 15-second cycle.