I saw the light

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KC8GTR, Nov 23, 2019.

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  1. WG7X

    WG7X Platinum Subscriber Platinum Subscriber QRZ Page

    Correct! Correct! Correct!

    CO2 lasers are in the infrared. They damage the cornea. These are the same frequency lasers that the Eye doctors use to reshape the cornea during the "lasik" process. The cornea will heal.

    The ultraviolet laser like the YAG Yttrium - Argon - Gallium laser light passes thru the cornea and lens of the eye and permanently destroys the retina. That will not heal.

    All this is with laser light that you cannot see with your eyes; but the hazards are real and they are not something to fool around with.
     
  2. WR2E

    WR2E Ham Member QRZ Page

    Not laser, but light... Way back around 1968 or so Popular Electronics had a project called "Talking on a Light Beam".

    A 1942 issue of QST mentioned it also.

    And... by the way... you've probably got several handheld data transmitters that use infra-red light already in your home!
     
    Last edited: Nov 23, 2019
  3. KA0HCP

    KA0HCP XML Subscriber QRZ Page

  4. K6CLS

    K6CLS Ham Member QRZ Page

    Good one :)

    Now, going off on a tangent... Euclid's parallel postulate is a conceit to make the rest of his epic work... And doesn't apply in our universe.... Nowhere is spacetime flat, it's always curved... Kinda fun to think about.
     
    WR2E likes this.
  5. KB7WG

    KB7WG Ham Member QRZ Page

    I can remember voice modulating a boy-scout flashlight in the 60s. But I can't recall the method, and I can't recall the detector. But it worked.

    And can find no mention of it on the net, but we copied it from a magazine. Like boys life or some other 60s print.
     
  6. WR2E

    WR2E Ham Member QRZ Page

    The one I built as a kid used a cad cell.

    This afternoon I spent some time trying to find the pop electronics issue (americanradiohistory.com has them all online) but I DID find it in Boy's Life. Your memory is not so bad!
     
  7. KK4NSF

    KK4NSF Ham Member QRZ Page

    Actually, using light to transmit information goes way back. Back in Napoleon's time, they used quite sophisticated mirror devices (called Helio somethings) to send morse-code like signals from stations spread a few miles apart.... and could relay messages across the country in less than an hour.

    And back in the 1960's there were all sorts of DIY magazine articles about modulating lazers, to send messages to receivers using photo-cells.

    I even recall one device that could hear folks talking inside a room by bouncing a laser off the window glass to a receiver device. Sound waves inside the room made the window vibrate.... and thus modulate the waves. As a kid, I wanted one of those!
     
  8. KC8GTR

    KC8GTR Premium Subscriber QRZ Page

    I know using light as a communication medium is old news...go ask Paul Revere hi hi .
    Curious as to how far the technology has progressed .
    Shooting laser down fiber optics is for the commercial boys , be more challenging to see how far by air .

    Once in awhile I can see satellites passing over head at night only because they are reflecting sunlight .
    If we , the average consumer and hams ever have the privilege to aim high , we can always set our sights , oops
    I meant laser pointers , at the satellites .
    Shine a light back up and with some crafty know how , track it and talk back and forth .

    We could always send up and inflate a gigantic Mylar balloon in space and bounce light and / or RF ( SUHF ? ) off the surface .
    Or what ever a good shape for a reflector used for outer space .

    Looking at the J-track website , there are thousands of objects floating around out there .
    I think most of those sats with their solar panels would be good light reflectors .
    A geo-stationary sat QSO via laser beam could be possible ?
    Guess there would have to be some issues worked out before anything like that will ever happen .
    There may be an issue with those optical sensored birds too .
    I can imagine what the government would say about shining your laser pointer at one of their sats !

    As for a QSO by way of the moon , that may require a major investment from the radio community to launch and successfully land our own mirror designed for our purposes .
    The mirrors left behind by our brave astronauts are designed to reflect straight back with very little divergence.
    Unless you like hearing yourself talk , not very useful for DX !

    So far from what I can tell , we pretty much advanced radio technology about as far as it can go .
    The generation of high levels of RF power has been mastered .
    The basics of TX'ing and RX'ing by radio waves has been mastered .
    New " modes " seems to be the latest rage but all rely on radio waves .

    Be great to have an option of another TX'ing method that is simple , affordable and very energy efficient while having great reliability and performance .

    Been curious about this laser light thing since childhood and now that I'm older and wiser , wonder if this be something fun and interesting to pursue .

    W.L.S. / KC8GTR
     
  9. KB7WG

    KB7WG Ham Member QRZ Page

    I think that we are on the verge of a great change in electronics. Involving THz and also the use of slower electronic speeds thru the use of meta materials. Actually controlling the true velocity of an electric signal. Down to sonic velocities.

    We will be able to slow a signal down, allowing us to sample it intensely. This will have the same effect.....as increasing our computation speeds by many multiples.

    We will be able to catalog all atomic combinations. Not to mention remote sensing.

    A tricorder.
     
  10. K3UJ

    K3UJ Ham Member QRZ Page

    There already was a metalized Mylar balloon in space. 100 ft. in diameter. It was called Echo, and they bounced radio signals off of it. It was very visible.
    https://en.wikipedia.org/wiki/Project_Echo

    Sixty years ago.
     
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