A CB radio reaches about a mile from a handheld on its stock antenna, a few miles truck to truck, and roughly 10 to 15 miles from a good base station antenna. Cobra's own figures for ideal conditions are 2, 5 to 7, and 10 to 15 miles, and it says those conditions "rarely exist." Then there's skip: on some days the ionosphere bounces 27 MHz signals hundreds of miles, which is why people swear they've talked across states.
Power isn't the variable. Every legal CB is capped at 4 watts on AM and FM and 12 watts peak on SSB (47 CFR 95.967). What changes the miles is the antenna, its height, the terrain and the noise around you.
How we worked this out
We started from the radio horizon, the same math that drives our radio range calculator: each antenna "sees" about 1.414 × √(height in feet) miles, and two stations can talk on a clear path when their horizons touch. We set those numbers beside Cobra's published range figures and the FCC rules on power and antenna height, read in the eCFR on October 21, 2026. Skip timing comes from NASA's solar cycle announcement and Wikipedia's article on sporadic E.
"How we pick" means research from rules, manufacturer pages and math. We didn't drive-test these numbers for this page. How we research.
CB range by setup
| Setup (both ends alike unless noted) | Antenna height | Line-of-sight limit | Realistic range |
|---|---|---|---|
| Handheld, rubber antenna | 5 ft | 6.3 mi | 3/4 to 1 mile (Cobra) |
| Car, magnet-mount on the roof | 6 ft | 6.9 mi | 2 to 5 miles |
| Pickup, tuned 4-ft fiberglass or 102-inch whip | 9 ft | 8.5 mi | 3 to 8 miles |
| Semi, mirror-mounted pair | 12 ft | 9.8 mi | 5 to 10 miles |
| Base at 30 ft to a pickup | 30 ft and 9 ft | 12.0 mi | 8 to 12 miles |
| Base at 60 ft to a pickup | 60 ft and 9 ft | 15.2 mi | 10 to 15 miles (Cobra's base figure) |
| Base to base, both at 60 ft | 60 ft | 21.9 mi | 15 to 20 miles over flat ground |
Line-of-sight limit = 1.414 × √(height in feet) per antenna, added. Realistic ranges are our estimates for open, flat country with tuned antennas, anchored to Cobra's CB range article and its handheld range article. Hills, timber and towns cut them.
At 27 MHz the horizon is a soft edge, not a wall. CB's long wavelength bends a little past the horizon and over low ridges, which is one thing it does better than GMRS at 462 MHz. But the signal fades fast once it's beyond line of sight, so the horizon is still the right planning number.
Look at the handheld row. Its horizon is over 6 miles, yet the real figure is about a mile. That gap is the antenna: a full quarter-wave at 27 MHz is about 9 feet, and a short rubber antenna wastes most of the 4 watts. Moving the same radio onto a roof antenna is the cheapest range jump in CB; our handheld CB guide shows which models make that easy.
Why the antenna beats everything else
Since the power is fixed, the antenna is the one part you can really improve. Three things about it decide your miles.
Length comes first. Longer CB antennas, up to the full 102-inch whip, radiate more of the radio's power than short loaded ones. A 102-inch stainless whip is the classic answer when you have a bumper or a sturdy mount for it; a magnet kit like the Wilson Little Wil is the compromise for cars.
Height comes second, and you can see it in the table: going from 9 feet to 60 feet nearly doubles the line-of-sight limit to a truck. The antenna also needs metal under it (the roof or a solid mount) and its tip clear of the cab.
Third is tuning. A mismatched antenna reflects power back into the radio. Check SWR on channels 1 and 40 and adjust until both are low; the full method is in how to tune a CB antenna, and mounts and coax are compared in our CB antenna guide for trucks.
AM, FM and SSB range
AM and FM share the same 4-watt carrier limit. FM sounds cleaner but doesn't reach farther in any way you'd plan around, and AM radios can't properly hear it. SSB is different: 12 watts peak envelope power, and an authorized bandwidth of 4 kHz against 8 kHz for AM (95.973). A narrower signal lets in less noise, so weak SSB stations stay readable when an AM signal would be gone. Both ends need SSB, which narrows who you can talk to. If distance with other sideband users is the goal, the Uniden Bearcat 980 is the common SSB mobile; the Cobra 29 LTD Classic is the AM/FM standard.
Skip: why CB sometimes reaches 1,000 miles
Skip is CB's party trick and its nuisance. A signal headed up at an angle reflects off an ionized layer and comes down far away. Two kinds matter at 27 MHz:
- Sporadic E: patchy clouds of ionization that show up mostly in late spring and summer in North America. Wikipedia lists CB among the affected bands and puts a single hop at about 500 to 1,370 miles. It can switch on and off within an hour.
- F2 skip: the higher layer, which carries 27 MHz signals mostly in the years around the peak of the 11-year sunspot cycle. NASA and NOAA announced on October 15, 2024 that the Sun had reached its solar maximum period. The cycle is now past that peak, so expect F2 skip to show up less often each year.
You can't plan a convoy around skip. What it does reliably is add distant voices to channel 19 and fill the skip zone with nothing, which is why your noise blanker and squelch settings matter on busy days (our CB adjustment guide covers them).
Is "shooting skip" legal? Talking to distant US stations is: the FCC's 2017 Part 95 rewrite removed the old 155.3-mile limit, as ARRL reported. Contacts with other countries are still banned, except Canada's General Radio Service (95.933(d)), and the 4-watt and 12-watt limits still apply.
How high a CB antenna can legally go
There's no height limit for an antenna on a vehicle or a handheld, according to the FCC's CB service page. For a base station, 95.941 caps the antenna at 60 feet above the ground, or 20 feet above the highest point of the building or tree it's mounted on, whichever is higher. Lower limits apply near airports (95.317).
That rule sets a practical ceiling. Two bases at the 60-foot limit have a line-of-sight limit of about 22 miles, and a base at 60 feet talking to a pickup gets about 15. Anything well past that, day to day, is skip.
What quietly cuts your range
- Terrain and buildings. A ridge between two trucks ends the conversation regardless of antenna.
- Noise. Alternator whine, LED light bars and inverters raise the noise floor so weak stations disappear. Sometimes a "range problem" is really a noise problem in your own truck.
- Squelch set too high. Cobra warns that setting squelch higher than needed reduces receive range. Set it just past the hiss.
- High SWR, a bad ground on the mount, or long thin coax.
- Dead batteries on a handheld, which Cobra lists first in its handheld range tips.
Getting more range, in order
- Raise the antenna and move it clear of the cab. Free or nearly free.
- Tune the SWR. Twenty minutes and a meter.
- Go to a longer antenna, up to a 102-inch whip, on a solid mount with good coax.
- Add SSB if the people you want to reach run sideband.
- For home, a base antenna up to the legal 60 feet does more than any of the above.
Skip the amplifier. It's illegal on CB under any circumstances (95.939), and it only helps you be heard, never helps you hear. The rest of the CB rules are in what is CB radio.
CB range vs GMRS range
For vehicles talking to vehicles, GMRS usually goes farther in practice: mobiles may run up to 50 watts and repeaters on hilltops reach well past the horizon. CB keeps its edge in rough terrain at short range and on skip days. Our GMRS range guide runs the same math for GMRS, and GMRS vs CB for off-roading compares the two for trail groups. If you're still choosing a radio, start with the best CB radios for trucks.
Sources: eCFR 47 CFR Part 95 (Title 47 up to date as of October 19, 2026): 95.317 · 95.933 · 95.939 · 95.941 · 95.967 · 95.973. FCC Citizens Band Radio Service page; Cobra support articles on CB range and handheld range; NASA, October 15, 2024; Wikipedia, Sporadic E propagation; ARRL on the 2017 Part 95 changes. Rules checked: October 21, 2026. How we research · Affiliate disclosure