“PI” and “T” Network Attenuators (also known as PAD attenuators) are simple networks to attenuate an RF signal with or without altering the impedance. Useful to add to the input of a high gain amplifier, that needs to be driven by a high power radio. If you want to attenuate 10w to 1w, (10dB) you will need to build the attenuator with resistors capable of dissipating 10w. For a simple recieve attenuator, you can use simple 0.25w or 0.5w resistors.
You MUST use non inductive resistors, not wire wound!
Below are the calculators to work out resistor values for different attenuation levels and impedances. The most common being the Pi network attenuator.