Mode General receiver

General receiver: NFM, WFM, AM, USB, LSB and CW anywhere.

Group	General & tools
Default frequency	145.5 MHz
Default sample rate	2 Msps
In the mode list	NFM / AM / SSB / CW

Step-by-step: Tutorial-General-receiver

What General receiver is

A general receiver demodulates what you click on: NFM, WFM, AM, SSB and CW, with filter, squelch and S-meter.

Frequencies and settings

Anywhere the radio tunes, 2 Msps.

Setting	Value
Start frequency	145.5 MHz
Tuning range of the mode table	1 to 6000 MHz
Sample rate asked	2 Msps
Lowest working rate	250 ksps
Channel width	1.6 MHz

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 NFM / AM / SSB / CW.

What OnAir shows

NFM, WFM (mono), AM, USB, LSB and CW (BFO pitch) on a channel clicked on the spectrum, with draggable filter edges and width presets, squelch (level or automatic against the noise beside the channel), AGC, de-emphasis, S-meter, frequency steps and audio recording to WAV.

Tips and caveats

• This is a tool for looking at the spectrum and recordings, not a decoder of one standard.
• Which radio: Usually yes for narrowband signals: an RTL-SDR tunes roughly 24 MHz to 1.7 GHz at up to about 2.4 Msps. Wide signals such as TV channels need a faster radio, and OnAir says next to the source what the selected radio can do.
• 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: These tools only look at the spectrum and listen. Receiving is legal in most countries, but laws differ on what you may use the content for. See Legal.

Related pages

• All modes, General & tools
• Supported radios, Troubleshooting, FAQ
• More in General & tools: Signal workbench, Spectrum explorer, Spectrum analyser