[R-390] Felton Electronic redesign of R-390A

[James A. (Andy) Moorer]

I have no experience with his engineering work - I am sure the receivers are
remarkable devices, and I am sure his work is top-notch.

But his reported sensitivity figure of .012 microvolts across 50 ohms can't
possibly be true.

Please refer to my "noise and sensitivity" page at:
www.jamminpower.com/main/noise.jsp

The short version is that a 50 ohm resistor at room temperature will exhibit
a .0266 microvolt "thermal noise" voltage. This has been known for decades.
A sensitivity measurement reports the voltage that is 10 dB above the base
noise floor. The absolute minimum sensitivity possible with a 50-ohm load
would be 10 dB above .0266 microvolts, which is about .084 microvolts. That
is the theoretical limit  - the actual sensitivity is probably much higher
than that.

James A. (Andy) Moorer
www.jamminpower.com


P.S. - even a receiver with a 100-200 microvolt input sensitivity is an
incredible receiver! No reason to inflate (deflate?) the numbers beyond
physical limits.


----- Original Message ----- 

> Good evening all:
>
> Does anyone have experience with the above mentioned company. He makes
some
> pretty impressive claims, but I haven't heard anyone ever mention him or
his
> work.
>
> http://www.feltondesign.com/
>
> Thanks for your input!
>
> Randy
>