21:23 UTC low 22 deg elevation pass
You can see the audio spectrum of the satellite. I could hear 3 beacons in a pass ( it was a low 22 deg pass).
There are 3 intervals (periods) – each abt. 23 seconds long:
a) A main period with a strong and deep noise dip
b) A second one with a lower noise dip
c) And a third one with a very low noise dip (not audible but visible in the spectrum)
So my conclusions are that ITUPSat is spinning with ~ 2.6 rpm.
I talked with my friend Colin, VK5HI about the rotation of ITUpSat. And he agreed. He think also that the spin period is somewhere between 2.69 and 2.76 RPM. The reason for the variance is that the satellite is “tumbling” hence has some level of nutation. He would suggest that the sat is spinning about one axis, but with a high level of nutation.
Rustem, Project Manager ITUpSat: Thank you for the spinning rate info. We expected ITUpSAT1 be spinning about one axis (axis towards the earth direction) and thumble with +/-30 degrees towards earth. We are using a magnet for passive stabilization.