Hi
Stefan,
it
seems these sidelines are about 10 dB down at +- 6 mHz. If they were
real, we'd surely see them in 424 uHz at DL0AO, but there's nothing
there.
What
is strange ist that the main carrier is shown 2 mHz below the 82 Hz
tick, wheras in reality ZEVS is only 10 uHz below nominal. So I suspect
that the real input samplerate is around 24 ppm higher than what
SpecLab thinks it is. This may cause periodic buffer overflows, where
samples are lost and phasejumps occurs. The sideline spacing indicates
that this is happening every 1000/6 seconds (~ 3 minutes).
73, Markus
-----Ursprüngliche Mitteilung-----
Von: DK7FC
<[email protected]>
An:
[email protected] <[email protected]>
Verschickt: Di, 18. Jun. 2019 17:53
Betreff: SLF: Sidebands arround ZEVS in 1 mHz
These days i'm calibrating the colours and angles in
my ELF...VLF
spectrograms. The colour of ZEVS is now calibrated to
deviate less than
3 deg. However producing a spectrogram in 1 mHZ FFT
bin width, i can see
sidebands of ZEVS.
Did someone else observe a similar effect?
In a first thought i would assume it is my timing
system that causes the
problem. But maybe it is ZEVS itselfe? Or even
propagation?
73, Stefan
PS: Capture attached.
