Do big FM radio stations transmit hidden broadcasts inside their radio signal?
Yes, some do; and not just the big stations. Even here at KVCB; our station broadcasts nine separate services for different purposes all encoded into our radio waves. Most services are designed for the public to receive with the right equipment, but a couple of them are "secret" and just for us! :)
Here's a complete list of the services we transmit on our channel for you to enjoy (I'll get to the secret ones in a bit):
- Our "main" mono analog audio service - This is our primary audio. All FM radio stations have this service. It's the audio of our basic student-produced programming designed for all radios with one speaker (that's why it's called mono). FUN FACT: All functional FM radio receivers manufactured since 1949 will still work because of this service.
- Our "main" stereo analog audio service - Most modern FM radios are stereo capable; meaning designed for two speakers, or left/right earphones. Human beings have two ears, so the best way to hear music on a radio receiver is in stereo where both the left and right ears get their separate sound. In this way, you get a full 3-D quality that allows you to place artists at any point from left to right. This requires the radio station to broadcast a stereo service that your radio uses to separate left and right for you to hear. Most FM radio stations, including KVCB, provide this service. Your stereo radio automatically decodes stereo broadcasts when they're available.
- Our RDBS (Radio Data Broadcast System) service - Many radios today can display special digital text messages that tell you what station you're listening to or a variety of other bits of information. FUN FACT: When you see "KVCB" or "VCS Radio" among other messages on your display, that's us! We sent that to you!
- Our special HD Radio services - These are four fully digital audio channels that provide static-free high-quality digital radio for HD Radio-capable receivers. If your receiver is HD Radio capable, it will automatically switch to our digital services. These include our "main" channel in pure digital sound! You can also choose to listen to our three other digital channels including student-produced and composed music; classic dramas and comedies; and school announcements. Not all FM radio stations broadcast HD Radio services. More information here. FUN FACT: We're the first high school and LPFM class radio station to broadcast HD Radio technology in the United States!
What about those hidden secret broadcasts?
Okay, here you go. We have two "not-for-public" services you'll probably never get to hear :)
- Our SCA (subsidiary communication authority) service - You don't get to listen to this one. This is our exclusive behind-the-scenes channel that allows our students to produce quality live shows for you on our main channels. Uses include talk-back communication from our control room to remote on-air talent as well as class broadcasting tests and projects for our beginner student broadcasters. We've experimented with other purposes, including PA services for classrooms. It's a fun channel for our students to work with, but it's just for us to have on hand when needed. FUN FACT: Years ago, FM stations would use their SCA channels to pipe in music to offices, elevators, and department stores as a subscription service. Because the FCC designates it as a limited communication channel, it's illegal to sell SCA-tunable radios to the general public! So, you'll have to trust us on this one. :)
- Our secret Morse code message service - We send a hidden message in International Morse Code every 60 seconds embedded in our broadcast signal! Why? Just for fun! Hint: look up "Frequency Shift Keying."