FUNCUBE-1 spin rate

Satellites & Observations
1

Greetings,

Few weeks ago I noticed that the waterfalls from FUNCUBE-1 observations were looking a little unusual. At first I though that it was in a special low duty-cycle mode, but now it looks more clear that it is not an on/off duty-cycle, but the signal is fading due to spinning.

What is interesting is that the spin rate is increasing, in fact, it has almost doubled during the last 3 weeks as you can see in the two example observations below.

Observation 83027 from 2018-02-20 (3 RPM):

waterfall_83027_2018-02-20T18-07-57.png800×1600 1.33 MB

Observation 94986 from 2018-03-14 (5.4 RPM):

waterfall_94986_2018-03-14T18-32-46.png800×1600 1.23 MB

This kind of happening is always interesting to observe, and is an excellent use case for the SatNOGS network. Please schedule passes for this satellite in the coming time so that we see what happens :slight_smile:

Alex

7 Likes
2

Sounds like a good example illustrating the need for a good circular polarised antenna system on the ground?
73.
Dave G8KBV

3

Yes. I use a turnstile which should be circular at zenith and linear close to the horizon.

Alex

4

Pretty interesting.

Latest observation of mine seems to show it’s still spinning faster.

https://network.satnogs.org/observations/112508/

Might try looking at a bunch of observations and make a plot of spin rate vs date

5

Indeed, it seem that now rotation is up at ~11 / 100 seconds.

It would be very interesting with a plot of rate vs time.

6

I might work on that today. I have a lot of free time before class today.
(It’s only 10 am but my class is at 3:15 xD)

7

An analysis from VK5HI at http://www.dk3wn.info/p/?p=86377

8

Interesting. So it seems to spin up during the times of direct sun light. Then eventually start to slow back down.

9

Spin rate is now decreasing again, it seems…
https://network.satnogs.org/observations/?future=0&good=1&bad=0&unvetted=0&failed=0&norad=39444&observer=&station=

waterfall_126325_2018-05-02T17-35-23.png800×1600 1.33 MB