OnAirDecode AM stereo (C-QUAM) with an SDR
AM stereo: C-QUAM on medium wave, stereo found by its 25 Hz pilot.
- Group
- Broadcast radio
- In the mode list
- MW stereo, 531 - 1602 kHz
What AM stereo (C-QUAM) is
AM stereo, C-QUAM (Motorola) on medium wave: the 25 Hz pilot found, left and right from the phase of the carrier, a stereo / mono indicator and the audio on the sound card; plain AM stations play as mono.
Frequencies and settings
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 MW stereo, 531 - 1602 kHz.
What OnAir shows
AM stereo, C-QUAM (Motorola) on medium wave: the 25 Hz pilot found, left and right from the phase of the carrier, a stereo / mono indicator and the audio on the sound card; plain AM stations play as mono.
Limits and what it was checked with
Checked with generated signals and impairments; recordings of real signals welcome.
Which radio you need
This is a shortwave mode, so the radio has to tune HF. An SDRplay, Airspy HF+ or an RTL-SDR in direct-sampling mode do that directly; with a HackRF an HF upconverter or a direct-sampling receiver is the usual route. A long wire or loop antenna matters more than the radio.
Receiving and the law
Questions about AM stereo (C-QUAM)
Can I decode AM stereo (C-QUAM) with an RTL-SDR?
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.
Is it legal to receive AM stereo (C-QUAM)?
Receiving broadcast radio is legal in most countries. OnAir cannot decode encrypted services.
Can I try AM stereo (C-QUAM) in OnAir without a radio?
Yes. Most modes include a built-in synthetic test signal, so you can open the screen and try the controls before you own a radio.