You can install your UHF antennas in several locations of your vehicle. You can have them placed on the roof, in the windows, in the trunk, or the fenders. A high mounting position is most preferred for better performance and greater efficiency, as it has as much metal mass as possible beneath the antenna. Another critical consideration is to maintain the antenna is not in the way of hatch doors or roof pillars wherever possible.
VHF/UHF antennas are commonly mounted in the following ways, in order of importance: on-glass mounting, hood or trunk grooves, fenders, trunk lid center, and roof center. This ranking is calculated based on the available ground plane and the clearance from obstructions provided by the position.
Take into account where your feedline can make its way into the vehicle while determining positions.
If you’ve ever seen police, fire, or commercial trucks, you’ll see that they have their antennas securely fixed to the body of the vehicle itself. This placement makes sense in such a way that it further enhances the ground connection.
It is also the ideal and recommended way to install it, but many are having second thoughts about drilling holes in the sheet metal, especially if the car is only leased. Direct installation or mounting is not always a practical option for many. However, it is then important that we are aware of the many different antenna mounting options we can try because they offer comparable performance, too.
Choosing Your Antenna
Typically, you can buy mounts and antennas separately. This works to your advantage since it allows you to combine and then match components one to another to meet your specific requirements.
Ascertain, though, that the antenna base you have got is compatible with your mount. For example, an NMO mount requires that you make use of an NMO antenna. Besides, N, 3/8′′, and UHF threaded stud mounts are offered on the market, too.
Mobile antennas are classified into three fundamental types: 1/4 wave, 1/2 wave, and 5/8 wave. Each one of them is distinct in its way. For example, the signal of a 1/4 wave antenna is directed at greater angles. Thus, making it more suitable for use in urban settings.
A 5/8 wave antenna is meant to refer the transmission toward the horizon, which is excellent for flat areas with poor transmission coverage. Half-wave antennas are used in situations where the ground is inadequate or nonexistent, such as on vehicles with bodies that are made of composite or fiberglass materials.
Size does matter. You will want to explore a small antenna or something that comes with a fold-over capability if you have a UHF antenna that stretches over the roofline.
You can mount up to a 40″ antenna on a trunk lid or bumper installation, which provides higher radiating performance.
Also, make sure to look for high antenna gain numbers, but we encourage you to maintain your skepticism somehow. When describing antenna gain, you should identify where you are measuring from so the reader may make an informed assessment.
In antenna literature, gain values are commonly stated in terms of dBi or dBd, which are both isotropic (i.e., dipole) radiators. Make sure you aren’t comparing different kinds of apples to each other.