The strength of the cell phone signal where you plan to mount the external antenna directly determines how large of an area you're able to cover inside of your home, office, or vehicle. If you have a strong external signal, you'll be able to cover an area similar in size to the advertised coverage area of the 4G cell Phone Jammer. If you have a weak external signal, the inside coverage area will be much smaller than advertised, which may require that you move up to a stronger system to obtain adequate coverage. Always keep this in mind when looking at the published square footage that is listed for each signal booster.

Understanding what the bars mean on your phone is also important to gauging how strong the signal is where you're going to be placing the external antenna. While there's no official standard for displaying cell phone signal with bars on a phone, and some phones have more or less than the traditional five bars, the rule of thumb still exists that each bar of signal is roughly 5 to 10 times the power of the previous bar. This is why it's important for people with low signal strength, such as one or two bars, to consider a stronger cell phone sigil legal mobile phone and GPS jammer crackdown by regulator yields GPS signal jammer than what is recommended for their coverage area.