[R-390] please help

[Bob Camp]

Hi

Back to the basics:

Is it -141 dbm / sqrt (Hz)? In that case it compares to a 50 ohm -174 dbm / sqrt(Hz) thermal noise level. 
Quick math would suggest a 33 db noise figure in that case.  

Bob


> On Oct 7, 2016, at 6:34 PM, <wb3fau55 at neo.rr.com> <wb3fau55 at neo.rr.com> wrote:
> 
> OK guys,  some years  back I read someone quote a noise floor of -141 DB for a "golden" R-390A. Please, if someone would,  convert that to microvolts.  I think it was in ER magazine.  I think they also quoted
> -139DB for 75A4.  Then someone installed  a 6GM6 in the 75A4 and it  was now as good as the R-390A. 
>  Entertainment-  HF is coming  back to life,  I have heard beacons on 10m for 3 days now! 73s Russ.
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