Reception modes: FM, AM, LSB & USB

The mode (or "demodulation") decides how the radio turns a signal into sound. The ATS Mini offers four: FM, AM, LSB and USB. Picking the right one is the difference between clear speech and an unintelligible whistle.

The four modes

FM

Wideband FM for the VHF broadcast band (64 to 108 MHz). Only available on VHF.

AM

The mode for shortwave and mediumwave broadcasters. If a station carries music and speech for a general audience, it is almost certainly AM.

LSB / USB

Single sideband, the efficient voice mode used by radio amateurs and many utility stations. LSB (lower sideband) is the convention below 10 MHz; USB (upper sideband) above it, and USB throughout on the aeronautical and marine bands.

Choosing a mode

• Tuning a broadcaster on shortwave or mediumwave? Use AM.
• Listening to hams, or utility voice like aviation weather (VOLMET)? Use SSB: USB for most utility and the higher ham bands, LSB on 40 m and below. If a voice sounds like a cartoon character, you are on the wrong sideband or slightly off frequency.
• Want Morse code (CW)? The ATS Mini has no dedicated CW mode. Listen in USB or LSB and the dots and dashes become audible tones. Tune slightly to one side to set the pitch you like.

A trick: SSB on a tough AM station

When an AM broadcaster is buried in interference or fading badly, switching to SSB and tuning carefully onto its carrier (sometimes called ECSS reception) can pull the voice out more clearly than AM does. It takes a steady hand on the fine tuning step, but it works.

In the app

Mode has previous and next buttons and a dropdown. VHF locks to FM (the mode controls grey out); the other bands cycle through LSB, USB and AM. When you recall a memory or tune an EiBi station, the app restores the right mode automatically.

Fine-tuning SSB by tiny amounts uses the radio’s BFO behind the scenes, so you’ll see the BFO value move in the status panel. If SSB voices are consistently off-pitch on a band, that is what calibration is for.