Basic How-To Information for Part 15 Radio Broadcasting

Basic Broadcast "How-To"

Here are descriptions of different methods to set up a Part 15 transmitter for a variety of uses. It goes without saying that with any transmitter setup you should select a frequency that is clear within your area to prevent causing interference to any licensed broadcast signal. For simplicity sake connections such as AC or battery power are not illustrated.

Basic Setup: Let's take a very basic example. You have a collection of AM band antique radios you have restored and you wish to have them play the old time radio programs that they once played when they were new. No matter if your recorded radio shows are on cassette (remember those?), CDs or even on your personal computer it's easy to play them back.
"Real Estate" Drive-by Radio: This example is popular for those using Part 15 radio transmitters to tell potential buyers about a house for sale. Sometimes people also use this sort of transmitter setup when they erect holiday light displays and they wish to share a message with visitors driving by. The major difference in comparison to the basic setup above is that the transmitter in this system contains built-in audio storage such as a built-in cassette recorder or solid state memory. You can then pre-record your message for continious loop playback to eliminate the need of leaving your stereo or computer on all the time. The graphic below illustrates the minimal connections required for this setup.
"Basic" Live Broadcasting: Elaborating on the basic setup, you will connect an audio mixer to your transmitter to allow you to play both program material (i.e., music, etc) as well as give yourself the ability to talk on air. Suitable "DJ type" mixers are available from a variety of sources. Besides the audio mixer and at least one audio source such as your computer or music player you'll need a microphone and compatible cables.
"Advanced" Live Broadcasting: The serious Part 15 broadcaster will desire to closely emulate the total radio station experience and try to achieve that "major market" radio sound. This setup is almost identical to the basic live broadcasting setup above with the addition of audio processing between the mixer output and the transmitter audio input connection. Some may even wish to add audio processing for the microphone as well. Basic audio processors like compressors can be purchased at stores specializing in musician supplies. If you use a computer for audio playback you can also find software programs that emulate compressors as well as broadcast audio processors. Some transmitters also offer some basic onboard audio processing as well. Besides providing the ultimate performance for community broadcasting the advanced setup can also provide high quality webcast audio which may be distributed over the internet.