What's This "Between-FM Stations" Stuff?

Have you heard those ads claiming there are FM stations between the stations? Is it for real? What’s that all about, anyway?

  • Jinx

Are[sub][sub]F[/sub][/sub] they[sub][sub]N[/sub][/sub] supposed[sub][sub]O[/sub][/sub] to[sub][sub]R[/sub][/sub] be[sub][sub]D[/sub][/sub] secret stations or something? Or are they talking about this?

Probably talking about HD Radio™ which allows AM and FM broadcasters to offer more programming digitally, tucked in the same bands as their normal broadcast.

You have to buy a separate receiver to get it; even Radio Shack has them.

More likely they’re talking about the subcarrier audio that is piggybacked on some FM station’s transmissions. It’s a seperate audio program which requires a special demodulator to receive; before the advent of satellite radio, ambience music companies like Muzak used to provide these receivers to busnesses who subscribed to their service.

No, I think DesertDog got it right. I’ve heard these ads, and they are advertising HD radio, or more specifically, HD radio receivers, which can pick up the additional stations.

HD receivers don’t get additional stations, they get current stations that have changed to a digital signal, which can be heard on a regular analog signal radio, or picked up with a digital receiver that allows you to hear additional feeds from the station (I think two more) that have (typically) different content.

So the extra feeds aren’t “between” frequencies–they’re “within” the former signal. But maybe they advertise as “between” because it would take too long to explain the technology in a 30-second ad.

Guizot, it was HD radio ads I’ve been hearing, and they do flat-out claim you will pick up stations between the stations, for one. But, if what you say is technically correct, then HD radio is a farse! Why not just call it DIGITAL RADIO!?!?!? Either way, one would need to buy a new receiver to get the digital signal.

But, could they be bold as to fool the public into thinking they’ll be getting more stations? Could it be that HD radio is more than just a digital signal? Or, is it a possible a digital signal is compressed (or smaller than its analog counterpart?) thereby allowing more stations to broadcast in the same limited space provided within the realm of the FM dial?

What’s the SD? :dubious:

  • Jinx

Yes, there are “extra” stations. As guizot said, by going digital, the station can use the same bandwidth to transmit multiple channels. For instance, in Washington, DC, public radio station WAMU-FM now has three channels, one of which still appears on their regular analog FM frequency. You need an HD radio to pick up the other two.

I don’t happen to know if broadcasters are required to provide extra channels if they switch to digital, but since presumably they are extra revenue streams, it seems likely that most do, or will.

Consider the similatrities with digital television as it now exists.

The TV station currently broadcasts an analog signal and a digital signal. The digital signal carries the same program as the analog station.

However, the TV station is permitted to broadcast more than one digital signal. Some stations use the additional signals to broadcast separate programming, others don’t make use of the additional programming options.

The same thing is true with HD. While most stations currently only rebroadcast their analog signal, a few (like WAMU) are making use of the additional options.

In the future, we’ll probably see both TV and radio stations use the additional options. So, no HD radio isn’t a fraud, it’s just at the early, early stage of development.

If these ads are saying that you can get “more stations,” then it IS misleading. With hybrid digital, you get the same station, giving you two extra feeds. (Or you get the same station with higher fidelity.) But to the listener, it’s all the same. Let’s say WXYZ goes HD, and now (with a digital receiver) you can hear, in addition to its “classic rock,” “soft” rock and “traditional” rock. You may think you’re hearing three distinct stations, but it’s really just one station giving you two additional feeds of different content.The point is that it’s the same station. And it’s not just FM:

Technically true but …

From the listener’s point of view, “station” really means “content stream”.

If I can now listen to 3 different programs where before I just got 1, what do I care if they all originate at WXYZ? They’re each playing a different song right now. They each represent a different genre. They each have (probably) different ads.

Whether they’re really provided by WXYZ (traditional), WXYZ-HD1 and WXYZ-HD2 or by WXYZ, their hated crosstown rival WCBA and their hated crosstown rival WMNO doesn’t matter beans to me.
So for Jinx’s benefit …

Yes, HD radio provides the capability to receive a bunch more streams of content, what you’re used to calling “stations”. Whether anyone in your location is actually broadcasting those extra streams is another question. Over the next couple years there will be a lot more new streams that require HD to receive, but in many locations today there are none.
That’s not really so diferent from traditonal FM. The radio in your car can receive ~100 frequencies or streams of content. In LA or NYC somebody’s transmitting on all 100, so you get 100 streams of content. Meanwhile, in Sheepfuck, Montana there are two FM stations, both dedicated to Hank Williams Jr. Same radio, a lot different entertainment value.

Your new HD radio can receive ~400 streams of content. But even in NYC there’s only about 110 streams available to be heard, the 100 tradional plus 10 new HD. So far.