This is actually an Oscilloscope Input question. I have rebuilt a Heathkit IG-102 RF signal generator. It is surprisingly well aligned after replacing all of its electrolytic caps and replacing the 2-wire cordset with a modern grounded 3-wire cordset and safety caps. The question is, using BNC connectors and 50Ω impedance coax to connect the output to the oscilloscope I have 2 input options. Set the input for 50Ω or 1MΩ impedance. Which should it be set to? At the 1MΩ the current in will generate a greater voltage signal? In this case, I am simply looking to get the highest peak waveform @ the correct frequency by adjusting the tuning slugs in the RF generator. @tautech

 

If your RF Sig gen can provide over 5V output use the 1M input or the scopes 50 Ohm input may be damaged.
Alternatively terminate it into a 50 Ohm feedthrough so to provide a balanced feedline then into the 1M input.

 

Nope, signal in in the ~10mV output range. So use 50Ω unless signal >5V?

Alternatively terminate it into a 50 Ohm feedthrough so to provide a balanced feedline then into the 1M input

Are you saying use a BNC tee with a 50Ω terminator at the scope input?

Thanks, Sam

 

Nope, signal in in the ~10mV output range. So use 50Ω unless signal >5V?

Should be fine then.

Are you saying use a BNC tee with a 50Ω terminator at the scope input?

That should be fine with sinewaves but a proper feedthrough better preserves signal integrity.

 

You mean a direct coax connect without any other fittings then?

 

You mean a direct coax connect without any other fittings then?

A proper RF gen expects a 50 Ohm load and the amplitude adjustment on your old one is probably set up for that.
Into HiZ the signal amplitude is probably 2x the generators settings unless it has a 50 Ohm and HiZ output setting.