Reasons for poor cell reception can be broke down into 3 main reasons; distance from the cell tower, obstacles between the cellular device and the cell tower, and construction materials. Here is an in depth break down of each of the 3 reasons.
Distance from the cell tower
This is usually the most obvious thing people think of when they are dropping calls or experiencing slow data. It's important to know the cell carriers are responsible for how many cell towers they put up and how much power they will put out. The reason for having cell towers is simple; it's about revenue. Rural parts of the US that don't have a lot of subsribers will typically be less covered, because the cell carriers won't get the revenue to justify the expense of the towers. Towers are very expensive to build and maintain. The output power or distance covered by a cell tower is regulated by the FCC and also limited to prevent overlaps between other towers. Revenue is also factored in with coverage area as it cost more to cover more.
Obstacles Between the Cellular Device and the Cell Tower
Mountains, hills, trees, and large buildings would be considered obstacles between you and the cell tower. Cellular signals can bounce off of objects and move around objects, but with each object an effect called attenuation (losing of signal strength) will increase. Dense forests and metro areas can cause cross-path interference in the signal itself. Mountains are simply insurmountable by cell signals. Another issue that falls along the same line is; inside large building such as malls and hospitals the farther you go to the interior the more obstacles the cellular signal has to overcome. In other words the size of the building itself is an obstacle.
It has been shown time and again that the biggest cause of weak cellular signal in buildings is caused by the construction materials used. Any type of metal is usually the number one culprit. Examples are steel buildings, steel roofs, low-e glass (metal oxide film), and energy efficient foil faced insulation. Thick concrete and mortar will also cause cellular signals to attenuate.
Cellular amplification by the use of a cell booster will overcome all the issues listed above. It is important to know that there are different types of products available on the market and it will be important to know what you're looking for and what to expect. We'll cover this in a different article listed below.