[Elecraft] Spectrogram plot interpetation

[Don Wilhelm]

Dave,

It doesn't look like anything is really wrong.

The 'hump' IS the passband that you are looking for.  The 'ripply' part can
be reduced by changing the sampling parameters in Spectrogram, but it will
take more time to process the complete waveform.  The narrow filters (like
700 Hz or less) for CW will display a pronounced peak in the center, but for
a SSB filter, it should be rather flat on the top of the passband.

It looks to me like you have the 2.5 kHz mod installed, and with that, I
would recommend that you set the Spectrogram markers at 300 Hz and 2800 Hz,
then adjust the BFO so that the majority of the 'hump' is centered between
those markers (actually it looks like you are quite close to that already).

The band noise that you are using should be fine - just keep your ears open
for any single signals that may appear - if a single signal is present, you
will see the pattern for that signal and not the broad spectrum that the
noise shows.

Set Spectrogram to show a 90 dB scale and the 'hump' should be higher on the
display and is a bit easier to see.

73,
Don W3FPR

----- Original Message -----

Would one of you astute guys please look at this and tell me what's wrong.

http://home.internetcds.com/~barbados/spectrogram.jpg
It's my K2 at 14MHz using FL1 (OP1) on upper sideband.

Source is just band noise.

Is this normal?  Do I need a noise generator?  Why don't I have a nice peak
instead of a ripply hump?