• Zess@lemmy.worldEnglish
    13611·
    11 days ago

    Nothing since a radio telescope isn’t a fucking speaker.

    • Daemon Silverstein@thelemmy.clubEnglish
      25·
      11 days ago

      I once saw a video of a person touching a grounded sausage to the metallic structure of an AM radio tower, the transmission was audible as the sausage was being zapped. If there’s a merely conductible thing grounded near the tower, I guess it’ll sort of “coil whine” (a well-known phenomenon when electrical components physically vibrate due to the passage of current), converting to sound whatever it’s being transmitted at the moment. This includes the tower structure itself, if the electrical grounding isn’t properly done or if there’s some grounding leak. Otherwise, a grounded thing touching the tower would suffice to convert the transmission into sound, if those radio-telescopes use AM modulation (I’d guess they do, because AM modulation is known for reaching longer distances than FM).

      • Hagdos@lemmy.worldEnglish
        12·
        11 days ago

        AM doesn’t reach further than FM, it’s just that historically we’ve been using AM at lower frequencies, and these travel further. You could transmit with FM just as well on these frequencies, and get the same range.

        These radio telescopes don’t transmit anything at all, they listen to radio waves coming from the cosmos. Much like a normal telescope doesn’t transmit light.

        • Daemon Silverstein@thelemmy.clubEnglish
          8·
          10 days ago

          historically we’ve been using AM at lower frequencies, and these travel further

          While I agree with that statement…

          AM doesn’t reach further than FM

          … i disagree here. Yes it kinda does, and there’s why: FM deteriorates with phase shifting introduced by phenomena such as ionospheric reflection, while AM is more resilient to it because it encodes information as amplitude variations instead of frequency (and therefore, implicit phases) variations. Also, FM needs more bandwidth than AM. Also, the overlay of two or more simultaneous AM transmissions is “more understandable” than two or more simultaneous FM transmissions laying on the same frequency. Both the three are the reasons why the modern aviation continues to use AM for comm between TWR and airplanes, as an example. Not just by historical reasons, it’s because AM is more resilient than FM.

          By “reaching further”, I don’t mean the range of propagation because, as you correctly said, it has more to do about wavelength and, therefore, the carrier frequency. By “reaching further”, I actually mean the capability for the signal to be correctly demodulated and minimally understandable at the end. If a signal can propagate across hundreds of thousands of kilometers (for example, between Earth and the Moon), but it can’t be recognizable at the other point (because the phases are all messed up to the point of being unable to be demodulated), then the signal (as in the content to be transmitted/received) couldn’t really “reach further”.

          Here goes an example: I live in Brazil, in the southeast. I was in Sao Paulo state (not the city) when I once managed to receive an English-spoken CB (Citizen Band, 11 meters, approx. 27MHz) transmission. Most of our neighboring countries are Spanish-speakers, the only nearest English-speaking country is Guyana (the nearest corner close to Jatapu River being 3,000 km from Sao Paulo in straight line), but I could tell by the operator accent that he was not from Guyana. The reception would be almost crystal-clear, if my receiving setup were better (I was using a RTL-SDR with a piece of long wire barely touching the outside of the antenna’s jack). While there are repeaters for CB, they’re not as common as VHF or UHF repeaters, where you can even find, for example, EchoLink repeaters, so the international transmission really made into my Brazilian home, and it was even daylight! I only could tell the signal because it was AM modulated.

          When we talk about deep space communication, sure some things change, but most of the same rules apply.

          These radio telescopes don’t transmit anything at all,

          Back in 1974, the former Arecibo radiotelescope was used to transmit the famous Arecibo message (some sources Wikipedia and Universe Today). So, while they’re most used for reception, they can be (and they were) used for transmitting as well. It’s not a straightforward thing, it’s not simply a switch to be toggled receive-or-transmit because they involve different electronic circuitry, but the structure, the dishes and the antenna, can both transmit and receive: for reception, it just interacts with electromagnetic fields, which induces an oscillating electrical current all the way through the structure until it’s filtered (through electronic components such as variable capacitors) and amplified by a receiver circuit, while as for transmission, it conducts an oscillating electrical current and irradiates it, depending on the antenna shape and properties.

          Much like a normal telescope doesn’t transmit light.

          It’s also a possible thing: https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiments#List_of_retroreflectors

        • cmhe@lemmy.worldEnglish
          51·
          11 days ago

          These radio telescopes don’t transmit anything at all, they listen to radio waves coming from the cosmos. Much like a normal telescope doesn’t transmit light.

          If you invert the flow of the electrons, a receiver becomes a transmitter.

          Speakers can become bad microphones and vice versa. Pretty sure that a radio telescope is a very bad transmitter for human music, but it could be possible with some changes…

          • stevestevesteve@lemmy.worldEnglish
            7·
            11 days ago

            if you invert the flow of electrons, a receiver becomes a transmitter

            Ehh not really. That’s kind of like saying if you invert the flow of photons, your eyes work as flashlights.

            “It could be possible with some changes” the changes would amount to removing the receiver and replacing it with a transmitter. In this specific case I’m not sure if a transmitter already exists at this antenna and it’s definitely possible one does, but that’s not a guarantee at all

            • cmhe@lemmy.worldEnglish
              6·
              10 days ago

              There is no such big differences between a light emitting (LED) and a light receiving diode (photodiode), they are just the reverse of each other. In fact photodiodes can even emit light, but very inefficiently. Same in reverse, LEDs can also detect light, just badly.

              It seems like most efficient energy conversion methods can be used in both directions.

              • stevestevesteve@lemmy.worldEnglish
                1·
                9 days ago

                An LED (or photodiode used as one) is a fairly simplistic device compared to an assembled receiver / transmitter. Just like you can burn gasoline in a car but you can’t push a car to turn the engine to make gasoline - it’s a complex system that really only works one way.

                • cmhe@lemmy.worldEnglish
                  11·
                  9 days ago

                  Nothing gets burned or otherwise destroyed when receiving EM radiation via a dish and converted it into electricity via a receiver.

                  Sure, the amplification stage of the process likely works only one way, and should be replaced in order to send something.

                  The one way process of burning oil to generate heat seems much more primitive than the energy conversion offered by a diode, TBH.

                  You can push or tow an electric car and charge their batteries. Because electric motors are also generators.

                  Even with your simplistic fossil fuel car in your example the alternator within can also be used as a motor.

              • Strykker@programming.devEnglish
                11·
                9 days ago

                Yes, but you would blow out most of the amplification circuitry in a radio telescope reciver if you tried to use it for broadcast at any kind of power.

    • tetris11@lemmy.mlEnglish
      3·
      9 days ago

      I’m actually surprised you got so many up votes for that level of technical correctness. This is a tough room

    • 404@lemmy.zipEnglish
      4·
      10 days ago

      Pump Up the Jam is an anagram of ‘Jump Up the Pump’.

      This song was played five times in a row at the funeral of director Stanley Kubrick.

      Techtronic’s home planet, Earth, consists of 70% water.

      If you isolate the individual drumbeats from this song and arrange them in a circle, it unlocks a cheat mode that allows you to pass through solid surfaces at will.

      • Malgas@beehaw.orgEnglish
        2·
        10 days ago

        When Pump Up the Jam was first broadcast, audiences feared it was real, and that jam would be pumped into their homes.

        The lyrics give clues to the location of a buried golden hare that has never been found.

        • 404@lemmy.zipEnglish
          2·
          9 days ago

          Technotronic got their name by combining the word ‘techno’, meaning a sort of dance music, and ‘tronic’ meaning ‘tronic’.

          The original 12-inch release of Pump Up The Jam came with a free horse.

          At 7.16pm on December 28th 1879, Dundee’s Tay Bridge collapsed as a train passed over it. 60 passengers lost their lives.

          Other musical acts whose names begin with ‘T’ include The Cure, The Isley Brothers, and The Velvet Underground.

          • tetris11@lemmy.mlEnglish
            1·
            9 days ago

            It shouldn’t be overlooked that the initials of the song as PUTJ, which was the Myers-Brigg personality type (problematic-unfettered-thoughtful-judgemental) of the lead singer who was combating Foot-In-Mouth disease at the time.

  • Daemon Silverstein@thelemmy.clubEnglish
    17·
    11 days ago

    Let S be an endless string which is a concatenation of every binary counting in succession, starting from zero all the way to infinity (without left zero-padding):

    S = 01101110010111011110001001101010111100110111101111…
    (from concatenating 0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, and so far)

    Let S’ be a set of every sequential group of octets (8 bits) from string S, which can be represented as a base-10 number (between 0 and 255), like so:

    S’_2 = [01101110, 01011101, 11100010, 01101010, 11110011, 01111011, …]
    S’_10 = [110, 93, 226, 106, 243, 123, …]

    I’d create an audio wave file whose samples are each octet from S’_10 as 8-bit audio samples, using a really low sampling rate (such as 8000 Hz or even 4000 Hz).
    That sound, that particular sound, is what I’d transmit to the cosmos: the binary counting, something with a detectable pattern (although it’d be not so easily recognizable, but something that one could readily distinguish from randomness noise).

  • smiletolerantly@awful.systemsEnglish
    17·
    11 days ago

    “Come here! I will help you conquer this world. Our civilization is no longer capable of solving its own problems. We need your force to intervene.”

    (Not really, but…)

  • Owl@mander.xyzEnglish
    16·
    10 days ago

    Either Never Gonna Give You Up or Darude - Sandstorm

    -The internet (10-15 years ago)