Observation 8224768: UVSQ-SAT (47438)

Satellites & Observations Observations
1

Hi!

I’m learning more about SatNOGS, and had a question about this observation. I see there is an artifact available for download, along with the audio and waterfall. I have tried to work with the artifact file, but have had no luck with it. What should I find in this file? How can I work with it? I have Windows and Linux PCs at home I can use.

This observation captured a UVSQ-SAT pass over the continental USA earlier this week, while the FM repeater was active. During this pass, N6UTC in California and I made contacts using D-Star and FM through the repeater, along with two other stations (KI7QEK in Arizona, N8RO in Texas) working in FM. The waterfall appears to show the difference between the FM and D-Star signals (D-Star signals appear to be the narrow signals, compared to the FM signals). The downlink audio from this pass was also captured in another observation, 8224776, but no artifact was available with that observation.

I posted a video showing that pass, where I worked N6UTC in both D-Star and FM, and two other stations in FM. That video is available at:

https://youtu.be/SEmyQBZRcmc

Where the D-Star transmissions in the observation audio sound like noise, you can hear N6UTC’s voice in the video. The video captured my voice directly, not through the satellite.

Thanks!

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2

Hi @wd9ewk! The artifact file is formatted in HDF5, which is a generic format used for holding binary data and metadata.

Specifically here, the .h5 contains the raw data used to generate the waterfall image. Having the raw data is useful to load and plot other waterfalls, extract doppler curves from the spectrum, and similar things.

  • Presently, saving the .h5 artifact is a default-OFF option for each ground station, so not many have it turned on. It represents more uplink data volume for the GS, which can be an issue for some situations.

The setting in satnogs-setup is at: Advanced → Artifacts → Enable uploading of artifacts.

It is fun to play your video and the obs 8224768 audio at the same time once you get them lined up :slight_smile:

It may be possible to pipe the audio recording into a D-star decoder, but this is not built-in in SatNOGS.

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