Choosing The Right CB Antenna
There are a variety of places you can mount your antenna and still achieve proper use from it such as, you vehicle’s roof, hood, bumper, and trunk. Of course each location can have its advantages so use your own preference and consideration after reviewing the details below:
Longer is better.
Longer antennas work better than shorter ones, so pick the longest antenna you can comfortably put on your vehicle. You can purchase quick-release accessories that allow you to quickly remove your antenna without tools, so antenna inconvenience may not be as big an issue as you think.
Higher is better.
The higher you can mount your antenna on your vehicle, the better. A vehicle's chassis can interfere with radio frequency signals reaching or emanating from your antenna, so you want to mount your antenna as high as possible on the vehicle for best performance.
Mount the coil above the roof.
For best performance, it's important to get the antenna coil above the roofline. This is particularly important for fiberglass antennas - the top of the antenna needs to clear the vehicle's roof. While not as crucial for base-loaded antennas, roof mounts will provide better performance than lower mount locations.
It’s important that a mount be sturdy enough to support the selected antenna. Whereas a small roof magnet mount would be well-suited for a short 2’ fiberglass CB antenna, it would be a poor choice for a heavy center-loaded 5’ antenna, as the momentum of the antenna while driving would likely cause the magnet mount to come loose. When selecting a CB antenna, make sure the chosen mount will provide adequate support.
Make sure it's grounded.
The vehicle's frame acts as an extension of the antenna, so it's crucial that CB antennas be well grounded. Poorly grounded or non-grounded antennas are the biggest cause of poor radio performance, so make sure your antenna has a good and solid ground.
An essential part of the overall electrical length of the antenna is the coax cable. You have to run the coax from the back of the radio to the antenna. If you mount the antenna in the back of the car or the mirrors of a semi, you'll need more coax cable. If your path has to run through the firewall, a window or interior linings, you'll have to consider the size of the connectors on the cable. It may be better to get cable with detachable connectors. Stay within 3 ft. segments to match the wavelength of the radio. If you have extra cable, don't cut it off instead, wrap it in a figure 8 and stow it securely.
Your antenna will be the determining factor of your system’s performance, so choosing a name brand quality antenna is my highest recommendation. The top three brands available are Firestik, Wilson and K40.
If you get a mounting kit made for your antenna, you'll avoid compatibility issues. If not, you'll need to make sure the antenna matches the threads in the mount to be able to screw into the mount. Also make sure that the mount you are getting will support the antenna you want to use. For antennas 4 ft. or longer, get a heavy-duty mount.
You need to make sure that your mount is large and sturdy enough to support your antenna. Magnetic mounts are handy and good, but they will not support a long (5 ft. or more) antenna, as the wind will make short work of it, whipping it back and forth then tipping it over.
CB antennas are grouped into three categories by load position, or where the antenna wire is wound into a coil. The optimal antenna length for CB frequencies is 102”, as this represents one quarter of a wavelength. Unfortunately, mounting a 102” (8.5-foot) antenna to a vehicle is usually not an option. In order to achieve that standard coils are wrapped tightly along the antenna to compensate the loss as well as keep the length of the antenna shorter. In other words, a longer length similar to that of the 102” whip is achieved on a shorter CB antenna by wrapping the antenna wire close together, forming a coil.
When deciding on a load position, keep in mind that the coil and about two-thirds of the antenna need to be above the roof line of the vehicle for the best operation. The three categories of antennas are determined based on their coil location:
- Base-Loaded Antennas
- Center-Loaded Antennas
- Top-Loaded Antennas
Most antennas are fiberglass antennas, which are fiberglass poles wrapped with a copper wire and coated with a protective material. While fiberglass antennas are cheaper, their advantage is that they can be mounted lower on the vehicle than other types.
Whip antennas are base or center loaded antennas topped with a long steel whip that can be tied down when not in use. That's common for professional drivers and magnetic antennas. They need to be mounted higher on the vehicle and aren't as efficient as top loaded antennas.
As the name implies, base-loaded CB antennas have their coil located at the bottom of the antenna. Often all-in-one magnetic mount and room antennas are base loaded. They provide simple mounting and can use thicker coil, which provides a higher Watt capacity. An all-in-one antenna refers to a product that contains the antenna, mount and cable in a single unit.
• Pros: Offers one of the simplest mounting and installation methods with the all-in-one models. They are less vulnerable to damage when struck and they can handle higher power outputs. The base-loaded models can use a thicker coil and generally have a higher watt capacity rating than top-loaded fiberglass CB antennas.
• Cons: The least efficient type of antenna relative to other load positions. An antenna’s coil needs to be above the highest vehicle surface for optimal performance, which results in fewer effective mounting options for base-loaded CB antennas. The coil load may be placed below a vehicle’s highest surface, but performance will suffer.
These antennas have their coil in the nearer to the middle of the antenna. This name is slightly misleading, as the coil is usually located nearer tothe bottom of the CB antenna rather than the middle. Center load antennas have a thick stainless steel shaft that makes up the bottom quarter to third of the antenna. The coil sits above this shaft, usually in a plastic housing, and the remainder of the antenna consists of a long, thin steel whip. Many popular professional trucking CB antennas are center-loaded.
• Pros: It is more efficient than the base-loaded antenna type, but less efficient than a top loaded fiberglass antenna. The high efficiency coil is capable of easily covering 120 channels at 1000-Watt power levels. This is typically a higher watt capacity rating than top-loaded fiberglass antennas.
• Cons: Less efficient than top-loaded fiberglass CB antennas.
The best mobile CB antenna is considered a top-loaded antenna, and is usually made of fiberglass.. Whereas the coils of base- and center-loaded antennas are usually sheathed in plastic, top-loaded fiberglass antennas utilize a thin wire that is wrapped along the antenna’s exterior shaft and covered with a protective layer.
• Pros: The top-loaded is the most versatile and cheapest and most effective antenna. It also has more mounting options, as the coil is located higher on the antenna, therefore, the coil can clear the body of the vehicle from several mounting positions. It’s possible to mount top-loaded antennas lower on the vehicle as the coil (which resides at the antenna’s top) is more likely to remain above the roof-line.
• Cons: Due to the thinner coil wire size, top-loaded CB antennas generally have lower watt capacity ratings. This generally isn’t an issue when using most CB radios, as 99.9% of all antennas can handle the 4-watt transmission limitation of all stock CBs.
No-Ground Plane (NGP) Antennas
No ground plane (NGP) CB antennas are designed to be used with RV's, boats, motor homes and other vehicles that don't have a sufficient amount of metal on them for a traditional CB antenna to function properly. CB antennas require a metal surface under them to create a ground plane (not to be confused with an electrical ground). Ground plane is important to signal propagation. If your antenna is mounted on a metal roof, the entire roof surface provides a ground plane, assuming that you don't have a sunroof. When installing a CB antenna on an RV, boat or any vehicle with no ground plane, a no-ground plane CB antenna kit is required. No-ground plane (NGP) CB antennas have the required ground counterpoise built in to the coax cable and allow for operation without an external ground. Traditional ground-plane antennas tend to have a15% to 20% stronger field strength than similar NGP antennas. Subsequently, it’s always preferable to use a traditional ground-based antenna if a good ground plane is available. Keep in mind an additional caution is that NGP antennas are not interchangeable with ground- based equipment
Once you have mounted your antenna please read my section on SWR to tune your radio.