SETI signal

Discussion in 'General Science & Technology' started by Pollux V, Jan 23, 2002.

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  1. ImaHamster2 Registered Senior Member

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    Kmguru, this would be an unusual use of the GPS system. The GPS system wouldn’t be used directly for determining antenna location. (Processing the GPS signal at the data collection site could provide extremely precise antenna location and timing.) The satellite signal is the important element. Used as a reference signal it would need to be very stable and have a complex waveform. SeekerOfTruth is likely correct that the GPS signals have those qualities. As long as the home antenna operated in the right frequency range this hamster feels that SeekerOfTruth’s system would work. (Bet some of those Hughes satellite guys are sufficiently interested in space science that they’d help.)
     
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  3. kmguru Staff Member

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    Huh...? I am confused. What timing are you reffering to? If you have a DirecTV satellite, the transponder already has a RT Clock. It can supply the necessary timecode to all receivers. The locations are fixed to earth structures. It is no different than antenna arrays that NASA uses. Except that they are bigger but few of them. We can have 10 million little ones.
     
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  5. ImaHamster2 Registered Senior Member

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    Kmguru, perhaps you are right. This hamster thought the GPS system had deliberately built in limits for security reasons. This hamster also guessed that the clocks on the DirectTV transponders would be insufficiently accurate for interferometry. Guesses aren’t as good as knowledge. Hehe.

    Some radars use a varying frequency chirp waveform as a reference signal. By convolving the reference waveform against the return signal a highly precise distance measurement is possible. Using similar techniques to compare reference signals from multiple sources to the data from the antennae, highly precise measurements of location and time should be possible. By using the measured distortion in the reference signals one may also “clean-up” the antenna signal. In this manner it should be possible to get clean signals with precise phase information from mediocre antenna data. That should lead to good interferometry.
     
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  7. Pollux V Ra Bless America Registered Senior Member

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    this all sounds like a plan but what guarantee do we have that the nice folks over at directv and NASA will listen to us? They probably feed their mail to goats.
     
  8. SeekerOfTruth Unemployed, but Looking Registered Senior Member

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    Imahamster,

    The GPS system had a component called Selective Availability or SA that randomized the clock output of the individual satellites as well as introducing errors into the ephemeris data that was transmitted by each satellite. SA was originally intended to degrade the accuracy of commercially available GPS receivers so that foreign powers could not use GPS as a targeting aid for their own ICBMs. Unfortunately, or not depending upon how you view it, commercial enterprises were smart enough to figure out how to remove SA from the signals. This is one of the primary reasons SA was turned off last year. Without SA, you have a fairly accurate real time clock in a GPS receiver and with processing such as that used in differential GPS you can position things down to milimiter level precision. This means you have an extremely accurate clock when looked at over large baselines.

    In regards to the use of Direct TV clocks for interferometry, I do not know how accurate the clock is, but knowing how accurate a GPS clock is and needs to be tells me that the Direct TV clock is not nearly as accurate.

    To use the GPS system you could have essentially two designs. In one, a separate GPS antenna would be physically coupled to a radio astronomy antenna with the exact distance between the phase centers of each antennna being known in advance. The GPS antenna and receiver would provide both accurate timing and position for the astronomy antenna. If you then 'listened' to the GPS signal on the astronomy antenna, you could perform a limited set of interferometry between the GPS antenna and the astronomy antenna as well as performing interferometry between different radio astronomy antennas.

    The second method would be to design a single antenna designed to look at the radio astronomy bands of interests as well as the GPS signals. This would be a little more complicated and would eliminate the possibility of doing interferometry between the GPS antenna and the astronomy antenna, but would potentially be a smaller and lighter package.
     
  9. kmguru Staff Member

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    The RT clock in my proposal does not have to be accurate for a specific instance of the signal. All you need is a time code as reference when the signal begins. Only one clock can do that. So there should not be any inferometry involved. After you collected those signals, they have to be sent to a master computer for analysis. This is where you need the accuracy and the spatial information. Then it can be sent back to the users for crunching and analysis.

    Technically, it is not difficult, someone has to have the will to pursue...
     
  10. ssivakami Registered Senior Member

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    Yes. I saw it too on a program on Discovery. Its supposed to have happened quite a few times. But these freak cases are not really taken seriously because apparently interference etc can cause them.

    - Sivakami.
     
  11. kmguru Staff Member

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    Is it interference or deliberate?

    What if a civilization far away scanning the galaxy and sending out focused transmission to a small area for a short time and goes to the next. By the time they come back to repeat, it may take a month, six months or a year. The universe is a big place.

    I have not read anywhere that someone analyzed the signal and found it to contain earth transmissions. I allways read that it was not repeated so they scratch that as a fluke....
     
  12. Pollux V Ra Bless America Registered Senior Member

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    Well one conclusion to what happened was that an armchair radio operator fired a message out onto the moon and waited for it to be reflected back at him, but with extreme luck it wound up being obsorbed by a SETI dish, and with more extreme luck wound up being exactly what they were looking for.

    On an episode of Sightings (old TV show on the scifi channel) this one guy who claimed to have worked as a janitor or something said that SETI recieved five separate signals from five different species in the Orion Arm (I believe but am not sure). Of course this guy is the only evidence the Sightings blokes had and they just ran his interview and showed some shots of the sky. Needless to say this means that there was next to no proof of this except for a janitor's testimony, and there was no proof that he had even worked there.

    Buttt there is always the chance that he was telling the truth, that we've made contact with species from another world. I really, really hope I live to see such an event.
     
  13. kmguru Staff Member

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    Here are the possibilities:

    We really made contact. We found exactly what we are looking for and we were able to decipher the prime numbers or whatever. Then chances are that it will be classified because, we want to learn more in secret in case we learn new technology that other countries will not. Free Enterprise.

    We made contact, but since it was not repeated next day. We ignored it. What a waste....

    We did not make contact perhaps because we are listening to radio and they are broadcasting television. Technology mismatch.

    No one is out there. It is probable too.

    Add your own spin. Conspiracy etc....
     
  14. Pollux V Ra Bless America Registered Senior Member

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    Yes, its true, at the moment it's just as likely that there really is no other civilization out there as it is likely that the universe is peppered with them. What a sad concept.
     
  15. wet1 Wanderer Registered Senior Member

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    Much as kmguru has mentioned, if another species or alien civilization was discovered, chances that Joe Q, Public would ever hear of it are slim or none. Military and political leaders would clamp a national security lid on it so fast that even the discovers would have spinning heads. The chances of learning something new for offense or defense of national interest would be the driving plot behind it. It well could be that our radar stealth tech was inspired by such tech. Who knows?
     
  16. SeekerOfTruth Unemployed, but Looking Registered Senior Member

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    Actually Wet1, the roots of our stealth technology go back to Soviet research in the 50's and 60's.

    Maybe they are the ones who received the signal.

    Please Register or Log in to view the hidden image!

     
  17. James R Just this guy, you know? Staff Member

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    <i>...if another species or alien civilization was discovered, chances that Joe Q, Public would ever hear of it are slim or none.</i>

    Wrong. There are United Nations protocols in place which deal with the detection of alien signals. It would be world news almost immediately.
     
  18. kmguru Staff Member

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    Only after it was deciphered by the super computer or some heavy duty resources. And you know who controls those resources?

    It is (the listening /deciphering technology) not in the realm of amatuers...at least not yet....
     
  19. kmguru Staff Member

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    I just got an email from Eman Resu as follows:

    wanted to ask in the SETI thread but am unable to do so. Why couldn't "civilians" simply build their own recieving network? Doesn't the advent of the dish networks allow us to couple the dishes and receive in parallel?


    (Pls check your username and password to post...)
     
  20. ssivakami Registered Senior Member

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    Makes sense. Occam's Razor.

    - Sivakami.
     
  21. Adam §Þ@ç€ MØnk€¥ Registered Senior Member

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    Many groups, like the UN, have various protocols in place to handle various things. But information release is still determined by the decisions of those who actually have it. If Australia's DSD receives a signal, I doubt very much that they'll call the newspapers first.
     
  22. kmguru Staff Member

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    What we have here is six blind people describing an elephant (I am one of them). What we need is to find out exactly what the method is for transmission (if any) and reception and deciphering of what signal. Then we can find out what the strength and weaknesses are in the process and if in today's technology something can be improved or the whole process is a waste of time for various reasons....
     
  23. Stryder Keeper of "good" ideas. Valued Senior Member

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    I can put forwards that there is a true possibility of life else where in the universe, but to make my suspicion more tangible, you'd have to look to the ideas of Modeling the universe in a computer to recreate it.

    (the understanding is if you input information from the point you start (with data you have collected) to a future point, you should have enough to Model a reverse of how things have been to get an understanding of the beginnings of the universe.

    Most will note this as being what Cavendish Laboratory, Cambridge intends to accomplish.

    Of course I would like to put the point forwards that those calculations would be lapse of other life forms that our own, since they (and perhaps an meteorite worm) seem to be the only evidence of ET life.

    This means that a Theoretical calculation has to be derived about how much life exists in our universe to input in the model. (that way if the model has any relevance on our universe it would prove the existance of life, in fact you could even point where!)

    My kind of assumption is from the big bang there was 0% life, but blocks that accumilate over years to create life (even if those blocks stayed frozen and inanimate for thousands of years), over some time you can imagine that life would spread throughout the universe from the first explosions and settle, possibly populating about 6-7% of the universe.

    Over time there would be a fluctuation in growth, admittedly all life would be stuck to their planets to begin with and some might find themsleves made extinct by changes to their environment.

    Life exists in 5% of the Universe, when the first evolved life starts taking to the star's, then there is a sudden (in a relative sense) growth to life populating worlds that would have been uninhabitable earlier. By this point, differing communications systems would have been developed.

    Suddenly life exists in an increasing percent of the universe, the only thing that controls its growth is War, Famine, Pestilance (Oh and something us humans created.... Capitalism!)
     
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