Mode CW

CW: Morse code from every signal in the window, speed and callsigns.

Group	Amateur: digital
Default frequency	14.02 MHz
Default sample rate	2 Msps
In the mode list	Morse, 14.020 MHz

Step-by-step: Tutorial-CW

What CW is

CW is Morse code sent by keying a carrier on and off. A skimmer reads many CW signals at once.

Frequencies and settings

Morse code on the HF bands.

Setting	Value
Start frequency	14.02 MHz
Tuning range of the mode table	1.8 to 30 MHz
Sample rate asked	2 Msps
Lowest working rate	250 ksps
Channel width	14 kHz

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is Morse, 14.020 MHz.

What OnAir shows

Every CW signal in a 14 kHz window at once: speed, SNR and text, callsigns highlighted.

Tips and caveats

• Checked with generated signals and impairments; recordings of real signals welcome.
• Which radio: An RTL-SDR can receive HF only in direct-sampling mode, which OnAir offers in its radio settings; results depend on the antenna. SDRplay and Airspy HF+ radios are better suited.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: Amateur radio signals are meant to be received. Receiving needs no licence in most countries; OnAir does not transmit. See Legal.

Related pages

• All modes, Amateur: digital
• Supported radios, Troubleshooting, FAQ
• More in Amateur: digital: FT8, FT4, FT2, WSPR, JT65, JT9, Q65, FST4, MSK144, PSK31, JS8Call, RTTY, SSTV, HamDRM, Olivia, Contestia, MFSK, THOR, DominoEX, Hellschreiber