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Ask HN: Are there any projects to do historical archiving of RF spectrum?

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Ask HN: Are there any projects to do historical archiving of RF spectrum?

#1

Post by adamgamble »

Something like archive.org but for rf spectrum. I'm not even sure if its legal, but I was playing with my SDR the other day and thinking of all the historical information that passes over the airwaves that is ephemeral. Being able to view this data after a major event would be amazing. Imagine listening to all the radio information as 9/11 transpired or during the coup attempt in turkey.

Obviously this couldn't be done everywhere all the time, but it would be interesting to be able to archive radio spectrum during major events.

A quick google search didn't turn up anything.

Re: Ask HN: Are there any projects to do historical archiving of RF spectrum?

#5

Post by pigeons »

Hard enough to get good coverage, and very hard to get the storage resources. There was a CCC talk about setting up coverage, but that was ambitious enough, archiving was mostly out of scope:

http://www.cw-complex.com/rfarray/

http://www.rtl-sdr.com/talk-monitoring-spectrum-building-dis...

Re: Ask HN: Are there any projects to do historical archiving of RF spectrum?

#6

Post by vitovito »

From my notes on a radio archiving project I'm doing:

> Could you record the entire radio spectrum and extract stations and broadcasts later?

> In the USA, the AM radio band is 540-1710 kHz, a spread of 1170 kHZ,

> http://rtl-sdr.better-than.tv/?page_id=237 states that spectrum recordings are also a function of how many samples per second you choose to record:

> 2.8msps - 44.8mbps = 5.6 MB/sec.

> 2msps - 32mbps = 4 MB/sec.

> 1msps - 16mbps 2 MB/sec.

> http://www.myradiobase.de/perseus/ has sample files. 3.5 minutes is ~360MB. 60 seconds of 1500 kHZ is a gig. All too much. 24 hours at 1MB/min is 1.5GB, but 17MB/sec. is 1.4TB. Spectrum recordings are out.

Re: Ask HN: Are there any projects to do historical archiving of RF spectrum?

#7

Post by derptacious »

This is super interesting! And if anyone else is curious about creating a project that monitors the range of RF amplitude and frequency at many data points around the world, then send me your contact info! I want to see a record of this spectrum (human and non-human made) in frequency and amplitude to see how much it is (and hopefully "has") changed in physical space. I think interesting things would come out of this data.

Re: Ask HN: Are there any projects to do historical archiving of RF spectrum?

#8

Post by adamgamble »

derptacious wrote: post #7

This is super interesting! And if anyone else is curious about creating a project that monitors the range of RF amplitude and frequency at many data points around the world, then send me your contact info! I want to see a record of this spectrum (human and non-human made) in frequency and amplitude to see how much it is (and hopefully "has") changed in physical space. I think interesting things would come out of this…

Any idea if its legal? I assume it is but I have no idea.

Re: Ask HN: Are there any projects to do historical archiving of RF spectrum?

#10

Post by x1798DE »

vitovito wrote: post #6

From my notes on a radio archiving project I'm doing: > Could you record the entire radio spectrum and extract stations and broadcasts later? > In the USA, the AM radio band is 540-1710 kHz, a spread of 1170 kHZ, > http://rtl-sdr.better-than.tv/?page_id=237 states that spectrum recordings are also a function of how many samples per second you choose to record: > 2.8msps - 44.8mbps = 5.6 MB/sec. > 2msps - 32mbps = 4 M…

Assuming most of this is dead air, don't you think this would be a highly compressible data set (even lossless)?
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