What is HD Radio?
First, let's clear up a few common misconceptions about HD Radio.
HD Radio Is NOT "High Definition" or Satellite Radio or Subscription-based.
HD Radio is NOT high definition. The name "HD Radio" is a trademark owned by iBiquity. According to the company, "HD" is simply part of their trademark and not an acronym for "hybrid digital" nor "high definition."
HD Radio is NOT satellite radio. It is broadcast alongside standard analog radio signals in the same frequency range.
HD Radio is NOT subscription-based. Listening to HD Radio is free, the same as any other publicly broadcast radio station, commercial radio or public radio. However you may need to purchase a new radio to be able to listen to HD Radio broadcasts.
Why digital HD Radio is better than analog radio
HD Radio has the ability to multi-cast, that is broadcast more than one audio stream on the same channel.
Because the signal is digital, there is no static. If the signal strength is not strong enough, the tuner may revert to analog mode. Sub-channels are not broadcast in analog.
HD Radio can broadcast data, including song titles and artist information.
The audio quality of HD Radio is generally better than analog radio. AM streams can transmit 40 or 60 kbit/s of data and frequency range up to 15,000 Hz are possible. This is roughly "FM quality." Most boradcast 40 kbit/s and will revert to 20 kbit/s if the signal is weak.
HD Radio FM streams can transmit streams of 100, 112, 125, or 150 kbit/s with a possible maximum of 300 kbit/s (if no analog is broadcast) and abilities including surround sound. Most elect to broadcast around 100kbit/s which is about equal to an Internet broadcast or streaming mp3 of the same bitrate. This is not "CD Quality," but it is generally better than FM audio quality.
Although there is no static or noise in a digital stream, there is quality lost when the music is encoded and compressed in a digital format. Higher bitrates are better, but critical listeners will be able to discern a ~100kbit/s HD Radio stream from a CD.
Not all radio stations broadcast HD Radio. Depending on your area there may be just a few stations broadcasting in HD. Large metropolitan areas usually have dozens of stations broadcasting in HD Radio.
How do I get HD Radio?
To get HD Radio you need to purchase a new radio, tuner or other device that is HD Radio capable. Many cars are being sold with HD Radio tuners. Portable devices are available as well as home audio equipment including stand-alone tuners, and receivers with built-in HD.
Because HD Radio is a proprietary format, device makers must pay a fee to iBiquity to license the HD Radio technology. Stations must also pay a royalty for the right to broadcast HD Radio. For these reasons the format has been adopted slowly and public awareness remains low.
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