SignalsEverywhere: Decoding HD Radio with an RTL-SDR

Corrosive (KR0SIV) from the SignalsEverywhere YouTube channel has uploaded a new video that explains and shows HD radio being decoded with an RTL-SDR.

If you are in the USA, you might recognize HD (Hybrid Digital) Radio (aka NRSC-5) signals as the rectangular looking bars on the frequency spectrum that surround common broadcast FM radio signals. These signals only exist in the USA and they carry digital audio data which can be received by special HD Radio receivers. Back in June 2017 we posted about how [Theori] was able to piece together a full HD Radio software audio decoder that works in real time. Later developments saw additional data such as traffic data and weather info extracted from HD Radio too.

Corrosive's video also shows a comparison between analog and HD Radio audio. We note that the "HD" doesn't stand for high definition, so audio quality is not really better than the analog stream. He also notes that the HD Radio data stream can contain multiple audio channels, and often they are not the same as the analog station it surrounds. One example he shows is a Simulcast AM radio station being rebroadcast via HD Radio.

HD Radio RTL-SDR Decoding vs Analog Radio

4 comments

  1. Brad johnson

    american HD radio is just a way for big corporate satations to jam the little stations,
    the digital signal is on someone else’s channel above or below the analog frequency….
    https://www.youtube.com/watch?v=1OiH2lg_fes
    what I would like to see hacked up is a pirate HD radio only transmitter to give the corporate boys a taste of the poison signal they are dropping on all the little stations.

  2. Dennis Nilsson

    “Really stupid as HD works really well.” HD radio doesn’t work well. It have to many dropouts and doesn’t have the same range as an FM-signal.

  3. Peter

    Canada allows HD Radio as well and I just read that it’s been approved for India (which already has DRM stations on the air). In my local market, stations don’t promote it and just stick their HD channels on an analog FM translator. The AMs listed at hdradio.com don’t even transmit the signal any more because … again … they put their money into analog FM translators. Really stupid as HD works really well. And, amazingly, more new cars are coming out with receivers capable of it.

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