Will RADE Be the Next SSB?

Every so often a mode comes along that genuinely threatens to reshape how we talk on HF. Fifty years ago, that mode was single sideband, which overtook AM as the dominant voice mode largely because it packed a signal into roughly half the bandwidth. Now there's a new contender aiming to do the same thing all over again.

FreeDV has introduced a new digital voice mode called RADE — short for Radio Autoencoder — which occupies half the bandwidth of an SSB signal, while reportedly delivering more natural-sounding speech than earlier digital voice modes have managed.

The Tech Behind It

According to Amateur Radio Digital Communications (ARDC), which funded research supporting RADE's development, the mode blends machine learning with classical digital signal processing techniques, and is capable of operating down to signal-to-noise ratios as low as -2 dB. Its design was built around three priorities that matter enormously for HF voice work: efficient spectrum use, strong speech quality, and power efficiency.

Starting to Show Up in Real Radios

Perhaps the most telling sign of RADE's momentum is that manufacturers are already beginning to integrate it directly into hardware. ARDC reports that a downloadable module is now available for certain FlexRadio models, letting users add RADE support directly to their rigs. Operators running other transceivers can still get in on it by running the mode through a computer connected to their radio.

Whether RADE ends up doing for digital voice what SSB did for AM remains to be seen, but it's a development worth keeping an eye on. More details are available from FreeDV and on the ARDC website.