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I know it's not everything, but if you are interested in this the New York Times has an excellent feature using the ATC tapes and some recorded phone lines in the military/air defense system.
http://www.nytimes.com/interactive/2011/09/08/nyregion/911-t...
sigidwiki is worth looking at, but it's more for classification: http://www.sigidwiki.com/wiki/Signal_Identification_Guide
This data gets lost with traditional archiving, which is squarely considers context (including temporal simultaneity across multiple objects) to be metadata.
These sorts of efforts can be partially retrofitted/approximated with timecodes on existing archived material, which may also be a separate, worthwhile endeavor to pursue.
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)?
I compressed '20090922_950_GLFS_outdoor.wav' (150 kHz - 1750 kHz) from the Perseus site [1] with some lossless compressors. In each case, I independently round-tripped the de/compression and the results were confirmed to be lossless.
The compression ratios are in line or slightly (but not overwhelmingly) better than what you'd expect [2] from audio:
original: 1.000
7zip-lzma2-xz-ultra: 0.820 (not a signal compressor)
wavpack-normal: 0.724
wavpack-high: 0.691
wavpack-hhx6: 0.593
[1] http://www.myradiobase.de/perseus/
[2] http://wiki.hydrogenaud.io/index.php?title=Lossless_comparis...
You would be better off decoding and storing that, but that gets into v& territory pretty quickly, depending on who and what you decode (definitely don't decrypt/crack).
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)?
there are commercial solutions that do this
Then you've got a data storage problem which has been covered.
After that you've got the propagation problem. Not everything is seen from everywhere.
In any event you might want to check out http://www.reversebeacon.net/
It's a project that's got a different "simpler" archiving goal. It is just to track spots of people calling CQ in the CW bands.
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.
Earlier quoted context omitted.
Any idea if its legal? I assume it is but I have no idea.
Listening is 100% fine in the USA. Transmission without a ham license, and in certain bands, will net you some fines and maybe jail time.