[Elecraft] Using K3's Pre-amp

[Adam Koczarski]

> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
> bounces at mailman.qth.net] On Behalf Of wayne burdick
> Sent: Friday, January 09, 2009 8:53 PM
> To: Dave Yarnes
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Using K3's Pre-amp
>
> The noise floor is your entire problem  :)  It's a fact that the preamp
> improves the MDS of the K3 by at least several dB. But if  your noise
> floor is S4, it will do not good at all, because all lower signals are
> already masked by the noise.

I just ran a noise experiment at my QTH yesterday. My typical noise is s7.0
S6.5 s7.5 on 80m, 40m & 20m respectively. With every circuit in the house
off, except the one the radio is on, and with only the power supply and the
radio on that one circuit the noise is s4.0 S4.75 s5.0. I turned on circuits
one at a time and recorded to S level jump for each. The 'home entertainment
center' seems to be the biggest contributor so I'll start there. Now I just
need to figure out how the switch off the neighborhood transformers and
silence my neighbors! :) 

I have some fairly large power lines across the street. Are they usually
strong contributors to noise?

You can see the resulting data here:
http://www.ka7ark.com/20080111QTHnoise/pics.html


Adam - ka7ark