Regarding Observation 14456221 … Can someone please explain to this newbie why this observation was status as “Bad”? sure looks like a signal in the waterfall to me… I had originally set it to Good, but it was later changed by someone.
Thanks
Hey @kn6bkt and welcome to the forum!
I’ve marked it as Bad as per my analysis the signals doesn’t seem to come from the satellite. Just in case you haven’t checked, this is the link for how we vet the waterfalls.
So back to this observation, here are the ikhnos results using the TLE of NasbSat-2 (67285):
With the red line, we see which curve the signals of NasbSat-2 would follow, as you can see this line follows the visible wide signals.
Now the purple line shows the curve of signals should follow if come from a terrestrial transmissions, you can see next to it these chirps that follow this curve, so these are terrestrial signals or noise.
So we are left with the signal at around 17:58.
Unfortunately in most cases due to the nature of the LoRa modulation, signals are not visible in the waterfall. If they are visible according to the transmission details it should be very wide, so the signal at 17:58 isn’t coming from the satellite, actually it comes from RAFS satellite from the same launch that transmits at the same frequency, this is why you can see it at the center as the satellites are very close to each other so they kind of share orbital data.
At 300s, there is something that is fairly wide but, it looks more like a terrestrial noise than signal from satellite, so my guess is that 95% isn’t coming from FOSSASAT2E26.
Let me know if you have any further questions or if something wasn’t clear.
Thank you! This is very helpful. I’m having a good time improving my ground station and look forward to contributing in the future.
73, KN6BKT
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