Potentiometer in parallel with gain resistors @ RF frequencies...

[ZappHappy]

I need to make small gain adjustments to correct the DC error into a double terminated cable (75 ohms).

Normally I would place a POT across a gain resistor but how will this affect at RF frequencies.

What is the best type of potentiometer for RF freq (<30MHz) ?

 

[KlausST]

Hi,

I'm not much experienced in HF, thus I'd try to keep it as it is.

You say you want to adjust DC error. So in my eyes you may decouple DC from HF (by a series capacitor) and run just DC at the pot.
To introduce DC to a HF path you may use an inductor.

If you want better assistance then please post a (hand drawn) schematic.

Klaus

 

[BigBoss]

Potentiometers are not adequate for RF signals due to very high capacitive effects.Smaller, Surface Mounting Multi-Turn Trimmer Resistances are better.