Signal strength

In telecommunications, and particularly in radio, signal strength is the measure of how strong a signal is. Typically, this is measured as voltage per square area. Higher power uses such as broadcasting use units of millivolts per square metre (mV/m²). Very low-power uses are most often in microvolts per square metre (µV/m²).

Expressed in decibels, 1mV/m² is 0dBm (a shortened dB(mV/m²)), or 60dBµ (often written dBu).

Some examples

• 100dBµ or 100mV/m²: blanketing interference occurs
• 60dBµ or 1mV/m²: the edge of a radio station's protected area
• 40dBµ or 100µV/m²: the minimum strength a station can be received

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