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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

INDI and VLBI

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INDI and VLBI was created by Ilia

It would be a really nice thing to join a social-driven or open network about VLBI (Very long baseline interferometry).
Since there is much difficulty to get different and far devices time synced, I propose a project aimed on the radio spectrum, surely possible implementations can be obtained using generic AM receivers @MW frequencies. Time sync between peers can be done using KPPS, which provide ~1uS timing precision and less than 300m GPS position precision (I supposed 1MHz observed frequency). Signals received by many peers around the World could connect to a public INDI Server Hub and anybody could observe what they want. Receivers are omni-directional, so the client can make interfere waves from the peers in software by adding delays on streams.
Is there anybody who uses an RTL-SDR dongle for radio astronomy like a LF receiver?
Ilias.
Last edit: 6 years 8 months ago by Ilia.
6 years 8 months ago #18182

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Replied by Jasem Mutlaq on topic INDI and VLBI

I have access to a 1.42Ghz super heterodyne reveiver, I don't think that counts!
6 years 7 months ago #18183

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Replied by Ilia on topic INDI and VLBI

Using intensity interferometry I think it is possible: applying an AM digital demodulator and a low-pass filter to its output (both digital) you can use it without problem. 1420MHz is the IF or the observed frequency?
I read that common satellite LNBs are used for radio astronomy in the microwave spectrum, and their observed frequency is around 10GHz. This can make much simpler the approach because the large diffusion of satellite dishes.
6 years 7 months ago #18185

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Replied by Ilia on topic INDI and VLBI

Jasem,
Also consider that this method is applicable on photon detectors also, the most difficult thing is to keep a good time sync. using low sample rates and low cut-off frequencies helps in this manner, but this means that longer integration times are needed to get higher SNR (improved by stacking signals). Having more antennas or detectors means improving SNR.
Radek is starting an astro social network where to discuss on this kind of interferometry. We'll have to discuss on the various issues which are included into this system there.
Ilias.
Last edit: 6 years 7 months ago by Ilia.
6 years 7 months ago #18186

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