[Elecraft] Re L34 Adjustment

[peter barville]

Ron, AC7AC wrote:

>OOps, I bet you were using a narrow bandwidth setting, Dave. My
>apologies. I rewriting my procedure quickly, I left out the instruction
>to select a wide bandwidth.  If you narrow down the bandwidth, you will
>start reading a "peak". That's because the filter suppressing the
>wide-band noise. At wide bandwidth settings, peaking the "birdie"
>suppresses the background noise producing a dip in the AGC voltage
>reading where the birdie is strongest and the signal-to-noise ratio is
>best. At narrower settings the AGC won't see the wide band noise and
>reacts only to the birdie. I have a hunch you were using a narrow
>enough
>bandwidth to be reading the 'peak'. 

>I set mine with a bandwidth of at least 1.6 kHz. If you have the SSB
>module installed, the OPT1 filter is best.  

                               ---------

Now I admit to being really confused. I do not notice any point of L34's
travel where it produces a dip in the R2 reading. I'm still not clear
how it can. If L34 is adjusted in order to peak the birdie, then surely
the AGC volts will increase.

Maybe (for some reason) I don't have enough adjustment available on my
L34, but I see no point at which the birdie becomes strong enough to
suppress the noise. Even if it did, then the AGC voltage the birdie
generates would have to be initially equal to, and then greater than,
that generated by the noise (otherwise it isn't going to suppress the
noise). So where/how can a dip occur?
-- 
72, peter g3xjs