What is a RF attenuator?
The RF attenuator is a device that will decrease a signal level by a specified decibel (dB) level while maintaining proper impedance matching at the input port and output port. 50 Ohm and 75 Ohm are the two most common impedance types for RF attenuators. BNC, N, SMA and TNC are common types of coaxial connectors available on RF attenuators.
decibel (dB) = 10 x log10(Pout/Pin)
The required dB level can be calculated knowing your input power and desired output power level (selection chart).