What is the lowest number on the radio?

The lowest number you will typically find on an FM radio dial in the United States is 88.0 MHz.

Understanding FM Radio Frequencies

The number 88.0 MHz represents the starting frequency of the FM broadcast band in the United States. This range is where most standard radio stations transmit their signals, allowing listeners to tune in and enjoy a wide variety of programming.

The FM Broadcast Band in the U.S.

The FM broadcast band is a specific segment of the radio spectrum allocated for frequency modulation (FM) radio transmissions. Understanding its structure helps clarify why 88.0 MHz is the lowest tuning option.

• Frequency Range: The band extends from 88.0 MHz up to 108.0 MHz.
• Channel Division: This entire band is efficiently divided into 100 distinct channels.
• Channel Width: Each of these channels has a bandwidth of 200 kHz (equivalent to 0.2 MHz).
• Center Frequency: The frequency displayed on your radio dial (like 88.0, 92.5, 107.9, etc.) represents the center frequency of a specific channel. This center frequency is located 100 kHz (0.1 MHz) up from the lower end of that channel's allocated bandwidth. This is why FM frequencies often end in an odd decimal, such as .1, .3, .5, .7, or .9.

Here's a quick overview of the FM band characteristics:

Why 88.0 MHz is Significant

• Entry Point: For listeners, 88.0 MHz marks the very beginning of the tunable FM spectrum. When you manually tune a radio, you'll start moving up from this point to find stations.
• Broadcasting Standards: Regulatory bodies, such as the Federal Communications Commission (FCC) in the U.S., define these frequency allocations to ensure organized and interference-free broadcasting.

While there are other radio bands (like AM radio, which uses kilohertz), for standard "radio" listening on an FM receiver, 88.0 MHz is the initial and lowest number you'll encounter.