The higher the antenna gain, the better performing the antenna correct? This is usually true but not always. There are a few other factors to consider. Here’s a brief, non technical explanation.
Gain
There are a couple of different methods that manufacturers use to measuring antenna gain. The results give a dBi rating. You will usually see cellular antenna gain expressed in 3 different ways
- dB
- dBi
- dBd
dB and dBd are the same. 0 dBd (unity gain) is about 2.15 dBi.
The higher the antenna gain the more concentrated it’s beamwidth. As shown in the illustration of omni directional antennas, a 0 dB gain antenna has a higher radiation pattern while the 5 dB is rather flat. Typically a 0 db (or unity) gain antenna would would work better in area surrounded by many trees, hills or high rise buildings while a 5dB would be better in flatter, open areas. A 3dB antenna is probably the best all around antenna for most travelers.
Yagi Directional Cellular Antennas
Yagi Directional Cellular Antenna
Yagi antennas have the highest gains and, because of their more concentrated beam width, are directional. A yagi is mounted on a building and pointed towards the nearest tower. Because of their more narrow beam-width, they do not make good antennas for moving vehicles. Stick with omni directional antennas for cars, trucks and RVs. If there a hills or other obstructions between your location and your carrier’s tower, an omni directional may work better. However, we have seen many instances where the higher yagi still out performs an omni directional even in these types of areas.
Need more info? Larsen has some excellent and more technical info on antennas on their website. You can also find cellular antenna advice on our web site.