[Elecraft] [K3] The Way We Rank Receivers (long)

[Edward R Cole]

Walter,

Have to chuckle - "ask what one thought would be rhetorical question" 
and some one gives you an answer!

Well, if you can get away from modern civilization and run without ac 
power low noise conditions can be found.
My KX3 is out mounted in my truck so don't have it to test.  I did 
turn on my K3 connected to triband yagi and am seeing S5 noise 
"floor" where there are no signals (preamp off).  Checking 6m I also 
see S5 but this is pointed at a local noise source and with ext 
Gasfet preamp on.  If I turn the 6-element yagi 90-degrees the noise 
level drops to as low as S3 with preamp on (K3 needs some kind of 
preamp when using 6m).  I also have the PR6-10 which I use on HF or 
6m if I turn on DIGOUT-1 which energizes the PR6-10 and disconnects 
the ext preamp.  It shows about one s-unit lower noise due to less 
gain than the Gasfet.

But with "two bars" if you actually measured noise power it would 
probably still be about -120 dBm or higher.  Still on HF that is *quiet*.

73, Ed - KL7UW

From: Walter Underwood <wunder at wunderwood.org>
To: Elecraft at mailman.qth.net
Subject: Re: [Elecraft] [K3] The Way We Rank Receivers  (long)


 > On Oct 25, 2016, at 2:31 PM, Edward R Cole <kl7uw at acsalaska.net> wrote:
 >
 > I wonder where in the world one sees a 20m noise floor that low 
when antenna is connected?  Only when I lived off the grid running on 
battery power did I see S0 noise on my radio (3.9-KHz with TS180S 
from a dipole).

Good point. Looking at the photo of my KX3 on top of Mount Willson in 
Henry Coe, I see two bars on the S-meter on 20 meters. That is miles 
from Silicon Valley. It was quiet and lovely, I could hear everybody. 
The filters were wide open, preamp on, and NR off. Zoom in and you 
can see for yourself.

https://www.flickr.com/photos/walter_underwood/17417496311/in/album-72157652448882921/ 
<https://www.flickr.com/photos/walter_underwood/17417496311/in/album-72157652448882921/>

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)



73, Ed - KL7UW
http://www.kl7uw.com
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