The industry has also responded with a technological push, too. You may remember the failure of AM Stereo in the 1980s and 1990s. A small number of stations, notably WLS 890 in Chicago, continue to use the C-QUAM technology. But the latest technology for both FM and AM is HD Radio.
Have you ever heard of it? Many people I've spoken with have not. It's denoted with this icon:
I'll focus on FM, where HD is having (or aspires to have) its primary impact. HD brings two things to FM: a digital signal that, in theory, has more clarity than traditional analog FM; and the ability to carry multiple channels on the same frequency. The former is touted by the industry as a great benefit to listeners, but it's the latter that the industry actually cares about.
Some FM stations choose to offer only one HD channel that invariably carries the same programming as the station's analog channel. Other stations choose to add a second, third, or even a fourth digital channel. These would be called HD2, HD3, etc in addition to the HD1 that's repeating the analog channel.
In the case of HD1, is the purported additional clarity of the digital signal meaningful? Not if you listen in an inherently noisy environment like an office or an automobile. Perhaps it is if you have excellent hearing (I don't anymore) and your environment is quiet, but even then it depends on engineering choices made by the station. Most broadcasters don't care about over-the-air fidelity. For decades they have altered audio to make it more understandable in noisy environments with a technology called compression. The stations won't tell you they use it, and you can't turn it off at your end. Some stations are more egregious users of compression than others. You would think that they avoid compression on their HD feeds, but I'm skeptical.
Multiple channels on the same frequency can be enjoyable, on the other hand. WUNC-FM, the dominant NPR station in this area, broadcasts indie rock and alternative rock on its HD2. Unlike a typical student-run station, WUNC-FM has a high-power transmitter on a tall tower. Therefore its HD2 has excellent coverage. See what's available in your area by visiting the promotional website for the technology, http://hdradio.com.
Will HD technology make a difference in the financials of FM stations? I doubt it, but I can't blame them for trying. HD has limitations. Every additional signal that an FM station adds will reduce the range of its existing signals. It takes several seconds for a receiver to recognize the presence of an HD signal; if you flip frequencies quickly, you'll never even notice that HD is available. It takes another several seconds to change from HD1 to HD2 on the same frequency, etc. And in some cases, HD1 will become unusable on the fringe of a station's coverage and the receiver will fall back to analog anyway.
If you want to experiment with HD, you may need to change your vehicle's audio settings. In my 2017 Hyundai, HD was disabled. I had to enable it in settings before the receiver would recognize any HD channel. I wonder how many people in similar situations don't realize that HD exists at all.
As for true digital broadcasting that drops the analog signal, Europe is moving forward. I don't see it happening in the U.S. anytime soon.
