[Elecraft] L34 on K2 tuning question?

[k6sdw]

Kevin....great advice! Don't know why I didn't use the Spectrogram software
in the first place instead of my "ears!" ....just checked and I was a ways
off the peak, but using the PC and Spectrogram I've gained some sensitivity
without raising any noise.

Good call Kevin!

73


Kevin Cozens-2 wrote:
> 
> Eddy Avila wrote:
>> Changes while tuning L34 on my K2 are very subtle.
>> Just barely hear L34 peak with the slug near the top
>> of the can....is this normal?
>> 
>> I'm just trying to determine if the receiver on my K2
>> is working as it should.
> 
> I recently went through a similar situation where I felt my K2 was not
> hearing 
> as well as it was supposed to be hearing. After checking for construction 
> problems, I went back over the alignment including re-adjusting L34. I
> came up 
> with a little tip on how to make adjusting L34 a little bit easier.
> 
> As you are probably aware, adjusting L34 is best done with Spectogram. It
> is 
> very difficult to tell when you have the maximum strength on the internal 
> signal with the lowest noise just by ear.
> 
> Take a look at the screen capture I made
> (http://www.ve3syb.ca/tmp/K2-L34.jpg) 
> while adjusting L34 on my K2. You will notice there are two cross style 
> cursors, one in red and the other in black.
> 
> Once you have the K2 set up and Spectogram ready to go (ie. you see the 
> internally generated signal), move the cursor so the horizontal part of
> the 
> cursor is just at the top of the internal signal (the black cursor) and
> left 
> click with the mouse to mark the level. Next, move the cursor to the top
> of 
> the noise floor (red cursor) but do not click with the mouse.
> 
> You can now easily watch for changes in the level of the internal signal
> while 
> watching the noise floor. When adjusting L34, this set up made it easy to
> see 
> when the internal signal was at its peak. You can left click with the
> mouse 
> during the procedure to move the cursor that indicates the level of the 
> internal signal as needed (ie. as it starts to get stronger) so you can
> tell 
> when you have hit the peak remembering to move the cursor back to the top
> of 
> the noise floor afterwards.
> 
> When adjusting L34 on my machine, I was easily able to see when the
> internal 
> signal was strongest. While adjusting L34 I never saw a change in the
> level of 
> the noise to the left of the signal. After the internal signal peaked, 
> adjusting L34 so it went further in to the can meant that the signal to
> the 
> right of the internal signal began to drop off at a sharper angle. On my
> K2, 
> the slug seems to have bottomed out and makes me wonder if a cap needs to
> be 
> changed so the optimum setting of L34 will be with the slug somewhere in
> the 
> middle of its range of travel.
> 
> I hope the idea about positioning the cursors to aid in detecting changes
> in 
> levels of the internal signal and the noise floor might be useful either
> to 
> you or to other people.
> 
> PS. I have discovered that Spectogram seems to work when run under Linux
> via Wine.
> 
> -- 
> Cheers!
> 
> Kevin.
> 
> http://www.ve3syb.ca/           |"What are we going to do today, Borg?"
> Owner of Elecraft K2 #2172      |"Same thing we always do, Pinkutus:
>                                  |  Try to assimilate the world!"
> #include <disclaimer/favourite> |              -Pinkutus & the Borg
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