[Elecraft] K2 AF noise level?

[Curt]

What am I hearing on my K2/100 when on exactly 7.000 plus or minus a few KC's I hear a steady tone when switched to the dummy load? At first I thought it was coming from my computer monitor but it's not. When I switch back to the antenna system the tone is gone or at least so attenuated I can't hear it.

k3ey


Ron D'Eau Claire <rondec at easystreet.com> wrote: Keith KD1E wrote:
But is it the AF amp?  I *think* (not sure) that I did a test with my K2.
Listen to a dummy load and hear the hiss.  Turn down the RF gain and the
hiss goes away.  I KNOW that was the case with my Omni V and I
*think* that's the case with the K2 as well.  If that's true, then the hiss
is from the IF stages and changing the audio amp will do little.

---------------------------

True, but you must turn down both the RF and AF gains controls. The "RF"
gain control (actually it controls the gain of the I.F. amplifier) has a
finite range. It won't silence the receiver. The AF gain control is also at
the *input* to the audio amp, so turn it all the way down as well to hear
the real noise output of the audio amplifier. On my K2, using sensitive
headphones, there's no background hiss from the audio amp. It's all coming
from the I.F and RF stages. I can hear the background noise increase when
enabling the Preamp with a dummy load connected to the antenna port, so some
of the background is originating all they way back in the RF stage. Of
course, that noise level is way below the band noise even up on 10 meters,
so it's not limiting the sensitivity of the receiver. 

But with the RF and AF gain controls at minimum, so I'll I'd hear is the
noise from the audio amplifier, my K2 is completely quiet.

Ron AC7AC

_______________________________________________
Elecraft mailing list
Post to: Elecraft at mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com