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Is Arduino killing the electronic hobby?

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fourfathom:

--- Quote from: RoGeorge on July 03, 2021, 11:42:21 pm ---How was it there, at SETI?
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I was barely there at all, and only for a few years.  Back around 2001 I had made a worthwhile donation, so that plus my tech experience and contacts led to me being invited to join the board of directors.  I got to hang out with Frank Drake, Jill Tartar, and many other ridiculously smart people.  I met with Paul Allen a couple of times, as the Allen Telescope Array was getting ready to go live.  Most of my participation was in the "raising money and support" area, but I occasionally pitched in on some tech issues.  Again, some incredibly smart and thoughtful people there -- I learned a lot.

Nominal Animal:

--- Quote from: fourfathom on July 03, 2021, 08:38:50 pm ---as communications technology advances the signals look more and more like noise
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Yes; and I think we should emphasize that this is not because of any transmission technology thing, it is the very nature of information.

In simple terms, it is mathematically impossible to distinguish between a stream of perfectly random bits, and perfectly compressed data.

Is it possible to use the radiation of ones own star as the "carrier", with perfect data compression?  The closer to such "perfect compression" piggybacking on natural radiation sources like stars is physically possible and feasible, the harder it is for even a technologically hyperadvanced civilization to determine that the output of a nearby star contains a compressed signal carrying data.

Indeed, it is the stupid and wasteful ones that are easily recognized and localized.  Makes for an interesting approach to considering possible reasons for the Fermi paradox: the stupid ones get wiped out, and the smart ones keep their environs in order.  Reminds me of why hospitals keep their surgeries meticulously clean, really.  :-X

fourfathom:

--- Quote from: Nominal Animal on July 04, 2021, 07:26:22 pm ---
--- Quote from: fourfathom on July 03, 2021, 08:38:50 pm ---as communications technology advances the signals look more and more like noise
--- End quote ---
Yes; and I think we should emphasize that this is not because of any transmission technology thing, it is the very nature of information.
--- End quote ---

Well, it's both, really.  We can send random-appearing data using simple modulation techniques (for example on-off AM carrier or simple FSK) and someone will still be able to detect the signal.  Even many near-Shannon-limit modulation methods don't hide the presence of the signal.  It's when we use spread-spectrum and wideband phase/amplitude modulation methods that the signal starts to become undetectable to receivers that don't know the details modulation method being used.

Of course I'm not claiming that we can necessarily decode the simple modulation, just that we will know there's something there.  Decoding it isn't going to happen unless the data is non-random looking. This is why I insist that Aliens use an obvious beacon and coding  if they want to communicate with us here on Earth.

Nominal Animal:

--- Quote from: fourfathom on July 04, 2021, 07:56:02 pm ---Well, it's both, really.  We can send random-appearing data using simple modulation techniques (for example on-off AM carrier or simple FSK) and someone will still be able to detect the signal.
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Perhaps the following wording works better?

You can detect the presence of noise, but it is mathematically impossible to distinguish between perfectly random noise, and perfectly compressed data.

If someone manages to control the output of a star, even if only at specific wavelengths where the output or a normal unmodulated star contain near-random noise, assuming they have good enough compression techniques, it is mathematically impossible to determine whether the output of any particular star is thus modulated from just examining the output of said star.

fourfathom:

--- Quote from: Nominal Animal on July 04, 2021, 08:20:01 pm ---You can detect the presence of noise, but it is mathematically impossible to distinguish between perfectly random noise, and perfectly compressed data.
--- End quote ---

Yes.

All I was saying is that some modulation techniques that are now widely in use will exhibit easily-detectable artifacts.  AM radio, even if carrying a pure noise signal, will have a strong single-frequency carrier.  There will be noise sidebands, but the carrier is obvious.  Even compressed data may have an overlying framing protocol, and this can display detectable patterns.  Other methods, such as spread-spectrum, can be under the wideband noise-floor and be virtually undetectable (without knowing the spreading code) even if they are carrying non-random data.  For true stealth, spread-spectrum carrying compressed (virtually random) data is the way to go. 

But AM modulation is inefficient.  As we reach for communications efficiency, we are heading more and more towards compressed data carried by efficient modulation.  This is less and less detectable.

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