[R-390] R390 Dave N3DT, ask and then what is the input Z of the IF?

[Jacques Fortin]

Roger, when you write: I suggest 150 uv into the IF deck at 455 and set the DC gain for - 7 volts on the DC load.
Would you mean 150µV EMF (Electro Motive Force) or 150µV if the signal generator is terminated in 50 ohms ?
This is because there is a 6 dB difference between the two....
And I believe it was the intent of the question from Dave, N3DT.

Many RF generators are calibrated regarding their output amplitude only if they are terminated in a 50 ohms load.
In that context, if the output amplitude is adjusted to 150µV and left open-circuited (or connected to a very high impedance) 300µV will appear at the output, as being the voltage of the internal equivalent source of the generator, right ?
And this is what we call 300µV EMF...
In the case of the R390-A IF module, because the input impedance is very high, are we talking about 150µV EMF or 300µV EMF needed ??


73, Jacques, VE2JFE