HD radio is a flop. Here are just a few reasons why:
- It sounds bad (especially if you are a critical listener) due to the low bit rate
- It is not robust (it does not work well) in comparison to analog AM or FM transmission
- It takes up a great deal of bandwidth, and as a result, it causes a lot of interference to other stations
- It's expensive for radio stations to own and operate, and they have to pay a lot of money for a license to use it
- It solves a problem nobody had. It is digital, for digital's sake
HD radio has another "technical" name: "IBOC", which stands for "In Band On Channel." The idea was that the digital signal would be transmitted in the same band as the analog signal, and on the same radio channel. The first part is true; the digital signal is transmitted in the same band. But the second part is not true; in fact, the digital sidebands are transmitted on adjacent radio channels, and that is why HD radio causes so much interference to other stations.
The proponents of HD radio have been less than candid about this issue, and the FCC is looking the other way.
HD-AM is the worst offender when it comes to interference. When you tune across a station, it sounds like a Soviet-era jammer. An HD-AM station actually takes up all or part of FIVE radio channels, rather than the approximately 1-1/2 channels than a standard analog AM station occupies. Due to the skywave propagation conditions that exist on the AM radio band, this interference travels for thousands of miles at night. It is an economic disaster for many small town radio stations.
The worst offenders on both AM and FM are the high powered stations-- especially the 50 kW AM signals. Many of these are owned by CBS Radio. They are one of the investors in the corporation that developed HD radio, so they are loyal supporters. CBS is the single biggest source of interference to other AM stations, coast to coast.
Most people don't even listen to AM radio any more, and that is due in large measure to the amount of interference-- which, to be fair-- is caused by a variety of sources. But HD radio is undoubtedly a major contributing factor to the demise of AM.
By the way, I forgot to mention that hybrid digital transmission also makes analog radio reception sound bad! It produces a "hissing" sound in the background. It makes AM radio sound like a cell phone, because they filter out the high frequencies to protect the digital sidebands. Otherwise HD-AM wouldn't work (it barely works, anyway).
Wouldn't you think that smart people would figure this out and abandon HD radio? A few have-- and many more would like to-- but their hands are tied by corporate politics.
Some people think that radio is going to become redundant, once broadband wireless Internet service is widely available. I'm not so sure about that. I think broadcast radio will have an important role to play for many years to come.
As an industry, broadcasters need to abandon this failed technology and shut off their digital jammers. Right now, they are just shooting themselves in the foot. Personally, I can't wait until the last HD radio exciter is carted out to the dump!