**What is a decibel (dB)?** A dB is *a unit used to express the intensity / strength of a signal like sound or electrical power.* **What is a milliwatt?** A milliwatt is *a unit of power equal to one-thousandth of a watt.* **What is a decibel-milliwatt (dBm)?** A dBm is *a unit used to express the power of a signal through a logarithmic scale with reference to one milliwatt.* **Because it's a logarithmic scale, a ... change in decibel-milliwatt value represents a ... change in signal power.** Because it's a logarithmic scale, a *small* change in decibel-milliwatt value represents a *large* change in signal power. **What is the dBm used to measure in cellphone signal boosters?** In cellphone signal boosters, the dBm is used to measure *the strength of a signal before and after amplification.* **What signal strength in terms of dBm is considered good?** In terms of dBm, a signal strength of *-70 dBm or better* is considered good. **What signal strength in terms of dBm is considered poor?** In terms of dBm, a signal strength of *-110 dBm or worse* is considered poor. **Is the dBm unit a part of the International System of Units (SI units)?** *No*, the dBm unit is not a part of the International System of Units (SI units). ...