The Science of CB Radios – Radio Waves

How Location Determines Signal Strength

Today, we’re going to get a bit nerdy in our discussion of CB radios. The fact is, if you want to purchase and operate any type of CB radio, you need to know about radio waves and how they reach their destination. Furthermore, if you want to sell radios like the specialists at CB Radio Supply, you need to know even more.

Ground, sky, and space

Like other transmitted communication, 27 MHz radio waves are not sent or received in a straight line. Overall, it depends on how and where the signal is transmitted. With CB radios, these waves are transmitted three ways:  ground, sky, or space

Ground waves are transmitted along the Earth’s surface. Theoretically, they are easier to receive as they can bend around buildings and go over hills.

Space waves are sent between two stations that are in the line of sight with each other. If you can see your destination from your antenna’s perch, then you can send the signal via space wave.

Sky waves are for long distance (DX) communications. The signal is shot high into the atmosphere at a sharp angle and reflected back to its earthly destination to span hundreds or thousands of miles. This type of transmission is best done at night when the atmosphere isn’t charged by the sun.

Sky waves and AM radio

You’ve probably experienced how sky waves work at one time or another if you’ve scanned the commercial AM dial during a long drive. Stations with high-powered antennas can be heard several hundred miles from your current location. In the 1960s and early 70s, when Top 40 radio was king on AM, you could hear a New York City station in Florida, a Chicago powerhouse in Kansas, and so on.

How do you know where the signal is coming from?

You may not know. Unless you climb up to the roof and search the sight line or follow the cable from your house to the transmission tower. In the end, you have to listen carefully to the CB transmissions. Local communications will most likely be space waves. Conversely, if you hear from someone in another country, then it will be sky wave.

To understand more about these waves and how your CB radio receives them, speak to a CB Radio Supply specialist.