Observation 2255533: CAS-4A (42761)

How do I open up the bandwidth of the sample. Is it sat specific?

Regarding Observation 2255533

It’s controlled by the transmitter you’ve configured the observation to receive. See https://db.satnogs.org/satellite/42761/ for what’s available. I presume you’re after the GMSK transmitter?

You can select is when you schedule your observation:

I’ve just scheduled that observation as GMSK for you, delete if you don’t want it!

I don’t mind at all that you have scheduled.

It was my understanding that the capture bandwidth was linked to the (transmitter), you have confirmed that, altho its not documented… its not much more bandwidth to capture all 3 signal from the bird.

I know a RPI4 could handle the post decoding of all 3 signal types.

Q: there is no way to set that on the station side?

This is not quite accurate.

There are a range of flowgraphs, and they all behave a little differently.

All flowgraphs will produce demodulated data, a waterfall display, and an audio output.
The audio output always has a sample rate of 48 kHz. What the audio output contains depends on the flowgraph. In the case of FSK, it contains FM demodulated audio. For CW and BPSK, the audio output is essentially the output from a upper-sideband demodulator, with the signal of interest nominally ‘centred’.

The waterfall bandwidth also varies depending on the flowgraph used. The CW flowgraph uses a fixed 48 kHz bandwidth waterfall, which is what you are seeing in this observation.

In the case of FSK flowgraphs, the waterfall bandwidth is tied to the baud rate of the transmitter (as listed in the DB), multiplied by a ‘decimation’ factor, which is calculated based on the baud rate and the audio output rate ( max(4,satnogs.find_decimation(baudrate, 2, audio_samp_rate)) ). Essentially it ends up being a minimum of 48 kHz, but can end up being wider for higher baud rates. For a 9600 baud FSK signal, the waterfall ends up being 57.6 kHz wide. For 19.2kbaud, it ends up being 76.8 kHz wide.

As to your point of demodulating multiple signal types in one observation, no, SatNOGS does not do this at the moment. While I’m sure this would be possible, it would likely be a satellite-specific thing, and would need someone to develop it!

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