[R-390] Official specs

[Ing. Giovanni Becattini]

Sure, everything has its limits and we always create a model of reality that is not completely true, but thanks to your help I finally have a clearer idea of how things should be done. Even if we start with wrong conditions... 

In the end the topic is not that important, but I was curious to understand it...

For the noise, here in Florence, Italy, it's hell, and even for the measurements I have to choose the right moment. I also had to chase two disturbers inside the house: one was the Wi-Fi extender, one of those that use the home wiring, and the other was an old MacPro 2008 that produces a lot of noise even when it's off (or better, when they tell us that it's off... because it's not off).

> Il giorno 9 ott 2024, alle ore 23:10, Jacques Fortin <jacques.f at videotron.ca> ha scritto:
> 
> Hi Gianni,
> That's pretty much it, yes.
> But does a R-390A input behaves as a 125 ohms resistor at all frequencies ? 
> I have doubts...
> And even if you can measure it's sensitivity as 0.5µV for 10dB of (S+N)/N, the actual ambient noise conditions will prevent you to receive any signal at this level.
> I do not know how it is going in Italy, but here, the ether was way more quiet that it is now 30 years ago...
> The received noise level at my location is S9 to S9+10dB, 24 hours a day, on all frequencies from 100k to 30MHz.
> Even a good noise blanker cannot get rid of it.
> Except when it rains ! It goes down to 2-3 S units.
> And I am still searching for the source...
> 
> 73, Jacques, VE2JFE in Montreal
>