[Elecraft] spectrogram question
Tom Hammond
n0ss at earthlink.net
Wed Apr 6 10:42:23 EDT 2005
Hi Andrew:
>I used Spectrogram to set up my K2's filters. When lining up the
>frequency peak with the marker for my preferred sidetone (650 Hz in my
>case), the typical display shows the usual bandwidth shape, plus a
>relatively sharp (and very narrow bandwidth) spike slightly offset from
>the center of the overall filter bandwidth. Something like this:
>
>http://www.photogs.org/filters.jpg
>
>Do I aim for putting the marker on the sharp peak (slightly offset from
>center), or the approximate center of the wider bandwidth shape?
It appears you already have it set correctly. You want the center of the
passband (not an errant peak) to be over the frequency marker.
Now, this having been said, that sharp peak you illustrated, is it there
ALL THE TIME? If so, that's very unusual... and it might indicate that
there was a continuous carrier (though weak) within the passband of the
filter when you were performing the alignment.
Did you use a noise generator or just band noise? I suspect band noise, and
if so, that might account for the singular peak.
73,
Tom N0SS
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