What is the Range of a CB Radio?
One of the questions that people new to CB radio operations frequently ask is, "What's the range of a CB radio?" or "What can I expect for CB radio distance?" These are good questions, but they are hard to answer. It's like asking how long it takes to get from one side of Atlanta (or any other large city) to the other. It depends on the day of the week, the time of day, whether there are traffic accidents or detours, and what route you take to get from one side to the other. Likewise, it's difficult to say what the range of a CB radio is because there are many variables that impact CB radios' range. Some say that you should be able to get 1-2 miles per foot of length on your CB antenna if all other factors are configured well. A quick rule of thumb is that you'll usually be within radio range if you see the person you're trying to communicate with. The main variables affecting range follow.
CB Radio Power Output
The FCC allows a maximum of 4 watts of output power for CB radios to avoid signal interferences with other devices, such as TV and emergency communication radios. That varies because a manufacturer can be fined for putting out a radio with excess power, so they produce output values between 3 and 4 Watts, and in rare cases, only 2 Watts. Tuning your radio will help it put out the maximum power.
Location and Environment
Range is determined largely by where you are. If you're at the highest Mt. Mitchell overlook on the Blue Ridge Parkway in western North Carolina for example, you'll achieve significantly longer transmit ranges and receive ranges than usual. On the other hand, if you're winding through a heavily wooded valley lined with rock walls, your range may be only as far as you can see the vehicle ahead of you on the twisty road.
The same is true in the city. If tall buildings surround you, you're essentially in an urban canyon that reflects signals rather than passes them on. If, on the other hand, you're in a desert area near Las Vegas or prairie in Kansas where there are flat, wide-open spaces, you'll get the best range. The principle here is clear: CB radio waves cannot transmit through solid objects.
For every rule, there's an exception, and here it is. When you're on a mountaintop, you'll be able to transmit down the mountain to those who are in your line of sight, thus increasing your range. Also, if you're in boats located in calm waters, range can be excellent, although radio waves don't like traveling through water.
Remember those math "story" questions in school? Well, here's one for CB operators. If you're traveling at 60 mph going north, and an oncoming car that is traveling south passes by, how long will it take to get one mile apart (assuming constant speed)? Every 30 seconds that elapses, you'll get one mile farther apart, so if your radio range is five miles, you'll only have 2 1/2 minutes until you're out of range. That certainly explains why most CB operators have more success maintaining contact with those who are traveling in the same direction, either in front or behind their vehicle.
The design of the radio, including the sensitivity of the receiver and the operation of the squelch, has an effect on radio range. Try to get a radio with a manual squelch, if possible. With a squelch, you can change the sensitivity of your CB radio to adjust for varying signal strengths. You can get signals from farther away using a lower squelch level. The downside is that you'll get more background noise. On the other hand, higher squelch levels allow you to reduce the background noise, but you won't receive weaker transmissions. If you have a manual squelch, you'll be able to tweak it to your liking.
Also try to get a unit with a receiver that has low sensitivity. Most modern CB radios have more than adequate sensitivity, which provides good reception. Having less radio sensitivity means that you can be more selective about the signal you choose to listen to. You easily can compare radio features on our CB Radios page.
Portable CB Radio Range
If you're using a portable CB radio while walking around in the shopping mall, your range may be as little as 100 yards. If you use portable units for communication between two vehicles, you can expect about a one-mile range. There is a glimmer of hope for increased range if you change the antenna. You may be stuck with the standard short, inefficient antenna that came with the unit. However, sometimes you can substitute a longer antenna that might provide a little more range, especially if you can get height working in your favor. Sometimes if you move a few inches, you can get a clearer signal.
If you use a handheld CB radio inside a car, the metal frame of the car is an impediment to incoming and outgoing signals. Hold the radio so that its antenna is as close to a car window as possible to get the best range.
CB Antenna Length and Height
There is general agreement that the most important thing that you can do to improve your effective range for both transmitting and receiving signals is to choose the best antenna, to properly tune it, to install it in the best position on your vehicle, and to provide the best possible ground plane and ground.
The taller your antenna is, and the higher up it is mounted, the greater its range will be. This is because a taller antenna has a lower angle of radiation, meaning the CB signal travels close to the ground for a longer distance.
stand tall and can make parking and avoiding obstacles difficult.
Long Range CB Antenna Types
The type of antennas with the greatest range are the stainless steel 102" whip antennas, which may not be practical for parking in garages, under trees, and so forth. The single center load antenna also has about the same transmit and receive range as the whip.
Dual fiberglass antennas, with an approximate range of 5-7 miles for four-foot length, have roughly a 25% increase in range for the same direction of travel compared with single fiberglass stick antennas. A four-foot single fiberglass antenna's range should be about 4-7 miles. The two types of antennas with the shortest expected range is the magnetic mounted antenna and the no ground plane (NGP) antenna, which, at four-foot lengths, have about a 3-5 mile range - only about 70% of that of the ground plane antenna.
Base Station Antennas
Base stations have an inherent advantage because many different types of antennas can be used with the system, and they can be mounted higher and in stable locations. That, however, makes it difficult to estimate the range of a base station, which can vary from 10 to about 50 miles. Between two base stations, you could have a range of about 20 miles. A well-installed system should provide about a 15-mile or more range. If you're contacting a mobile CB station, you may have a range of ten miles or so. Just as with mobile radio antennas, the surrounding environment plays a significant role in determining the range.
What is skip?
CB radio are not intended to reach long distances, but sometimes they can, due to atmospheric conditions. Although CB radio waves usually just go through the atmosphere, once in a while they will bounce off the ionosphere and travel back to Earth. How far they "skip" or bounce depends on the time of day and whether there are solar flares at the time. Under the right conditions, you may find that your radio is receiving signals from a hundred or more miles away. Be aware that it is against FCC regulations to establish contact with distant stations (DX) more than 160 miles away, so the skip phenomenon may be only an interference, noise that is keeping you from talking to your nearby buddies.
In fact, one of the biggest thrills for an amateur radio operator, and even a lot of CB operators is picking up a transmission from hundreds or even thousands of miles away. We have talked to a customer in southern California that regularly picks up CB skip shooters from Oregon, Idaho, Hawaii, and even Australia! How does that happen, though? How can you pick up transmissions from hundreds of miles away on a CB radio that can only transmit 5-10 miles?
Bouncing Off the Ionosphere
When someone is "shooting skip", it means their CB signal is going very high up in the sky and bouncing of the ionosphere, an upper region of Earth's atmosphere. The ionosphere usually makes a good reflector for CB radio waves, but is better when there is more solar activity. Any decent radio and antenna can achieve this to some degree, but usually the ones you hear are doing on purpose.
If you have ever picked up skip shooters, you may have heard them saying things like "CQ", "DX" or asking for a good copy. These are CB hobbyists that have most likely tuned up their radios and/or are using large CB antennas in an attempt to transmit as far as possible. Unless you have a system like this yourself, don't plan on talking back. You will not be able to cover the distance.
What is the point?
So why do people spend the extra time and money to send a signal thousands of miles that they may not get a response from? Why climb Mt. Everest. It's there. People do it so they can say they did. Yes, you can pick up the phone or hop online and be in contact with someone around the world. You can hop in a car and and drive from Oregon to California in a few hours. Hiking there on foot is a much better tale, though. Contacting someone a thousand miles away on older tech like CB radios is still an impressive feet, even if there are easier ways to do it today. Have you ever picked up skip? From how far away?
How can I increase CB range legally?
Although the FCC limits CB radios to a standard 4 Watts of power, there is an exception. If you want the best range, you may want a radio with single sideband (SSB) capability. SSB radios, such as the Cobra 148 GTL transmit at approximately 12 Watts, or three times the normal power. The potential drawback is that the receiver must also have an SSB radio.