[Elecraft] Tuning L34 on K2 - The 'Signal to Noise Ratio' method

[Tom Hammond NØSS]

Hi Ron:

>Bert, DL8BDF, brings up a good point bout the L34 adjustment. The manual
>does say to tune for best "signal to noise" ratio.
>
>If  the K2 tuned microwave frequencies, that would be a significant
>concern. Up in the VHF region and above we would be doing everything to
>improve the S/N ratio, since the internal noise in a receiver up on
>those frequencies is what limits the sensitivity - the ability to "hear"
>signals down at the noise level.
>
>That's not true on HF, however. Even up on 10 meters it's quite obvious
>that at minimum selectivity the noise being picked up by my antenna
>completely overwhelms any noise generated within the K2.  So why the
>comment about setting L34 for best signal to noise rather than peak
>response?

I had the same (mental) question for quite a long time, but about 4-5 
months ago I was dinking around with L34 (no recollection why), and even 
'earballing' the adjustment, I did notice what I perceived to be a distinct 
drop in relative background at a point just inside the point of maximum 
received signal... maybe 1/2 turn (into the can) before reaching max 
signal. I was so surprised to hear it that I tried it several times, just 
to confirm that I was hearing what I thought I heard, and each time I 
noticed the same thing. So I now do believe that there was some thought 
behind the statement.

NOTE that I have NOT (yet) performed any quantitative measurements to 
confirm my beliefs.

73,

Tom  N0SS