Potential divider as an RF attenuator. What about output phase?

[neazoi]

Hi I want to use a simple potentiometer as a simple HF attenuator. That is one end to the receive antenna, the other end to the ground and the wiper connected to a circuit.

What is the phase of the signal on the wiper of the potentiometer, compared to the input of the potentiometer? Does it change on the different settings of the potentiometer or not?

 

[KlausST]

Hi,

A standard potentiometer usually is not suitable for HF.

An ideal resistive divider should give no phaseshift, this is the only good information.
A potentiometer is not ideal:
* there is stray inductance
* there is stray capacitance
* the output resistance and impedance depends on pot setting ... and it will give some feedback to the input.

Inductance and capacitance form high pass filtering, low pass filtering and combined it will give some resonances.
All this is unknown for a standard potentiometer. And varies with frequency...not what one wants.

You see there is a lot unknown...

Klaus