[ARC5] Some info on the S-38 - receiver sensitivity.

[Kenneth G. Gordon]

On 11/20/2015 10:43 AM, Fuqua, Bill L wrote:
> >    If you have an antenna sufficient to hear atmospheric noise on HF that is
> >    the best you can do other than improving the effective noise bandwidth of
> >    the receiver.

Well, yes, but...

> > That is why the application of low noise figure devices are not common or
> > necessary in HF receivers.

I would only disagree with this in one particular detail. The levels of 
atmospheric noise, at HF, and even at LF, are not a constant. 

There are times, possibly very few, when atmospheric noise at HF is 
unusually low. At those times, I prefer to own and operate a receiver which 
exhibits the lowest possible internal noise figure. 

I have never been particularly concerned about adjacent channel 
interference, never having lived near enough to a nearby transmitter to have 
experienced any long-term deletrious effects from such.

But, I have experienced, often enough for me, times when ambient noise 
levels were low enough that receiver internally-generated noise became a 
limiting factor for how weak a signal I could reliably copy.

To me, that is unacceptable.

Ken W7EKB