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2-FSK Data

Binary frequency-shift keying: bits toggle between two tones. Sent in short packets.

Bandwidth

~12 kHz

Category

data

Duty

Bursty

Best demod

NFM

How it looks on a waterfall

Two parallel rails that light up together in short bursts.

Where you'll hear it

POCSAG pagers, telemetry, AX.25 packet, some IoT links.

See it live

SPECTRA synthesises 2-FSK Data in your browser, so you can watch its waterfall signature and hear it demodulated without any radio hardware.

Open the live receiver →