ad: Morse-1

Bouncing radio signals off the Moon? Yeah, but on 10 GHz?

Discussion in 'Satellite and Space Communications' started by VK7HH, Sep 28, 2019.

ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: Left-3
ad: Left-2
ad: L-Geochron
ad: abrind-2
  1. SM0AOM

    SM0AOM Ham Member QRZ Page

    A spherical chicken in vacuum still has heat losses due to radiation.

    If the chicken may be assumed to be a thermal "black-body" the Stefan-Boltzmann radiation law may be applied.

    If the inward radiation energy received from the microwave antenna is equated to the energy re-radiated due to infrared radiation, the absolute temperature at which the thermal equilibrium sets in may be calculated for both cases; far-field and near-field.

    This is "left as an exercise for the reader".

    73/
    Karl-Arne
    SM0AOM
     
    AI3V likes this.
  2. K6CLS

    K6CLS Ham Member QRZ Page

    I'm imagining an impossibly dense spherical chicken, compressed smaller than an atom. So compact that an infinite stream of chickens falls in to it from all around. The chickens fall forever and are both shredded and not shredded on their way in. Across the universe after billions of years we can see the shreds turn in to microwaves... Not sure what Boltzmann would say about this.
     
    AK5B and AI3V like this.
  3. VK7HH

    VK7HH Ham Member QRZ Page

    Yes, one of the reasons why having WSJT track it with your radio over CAT control automatically is handy!

    Also - no chickens were hurt in the contact attempt...
     
  4. AI3V

    AI3V Ham Member QRZ Page

    I know the answer to which came first :)

    IMG9520190602951544325971.jpg

    20190924_135341.jpg

    Rege

    P.S. WARNING: You may observe different results depending on exactly when you are on the space-time continuum.
     
    Last edited: Sep 29, 2019
  5. AI3V

    AI3V Ham Member QRZ Page

    A Shout out to the OP.

    All kidding aside, it is my humble opinion that anybody who successfully reflects signals off the lunar surface shows a outstanding mastering of the radio art.

    Well done Sir!

    Rege
     
    AK5B, VK7HH and K0UO like this.
  6. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    I agree with the 3 hours cooking time on the complete chicken, however when the body temperature only Rises a few degrees which is exceeding the RF exposure guidelines by quite a number. The maximum permissible exposure that IEEE set up a number of years ago and similar programs are used by many countries, deals with controlling body heat worldwide, called maximum permissible exposure.
    With a small amount of temperature rise the body can be affected, you can start having damaged in the eyes and male reproductive organs. As body temperature rises to 106 to 170° Fahrenheit damage does start occur at microwave frequencies on body parts. The eyes are made up of mostly water, we don't have to boil water in the eyes to cause serious damage.
     
  7. SM0AOM

    SM0AOM Ham Member QRZ Page

    The current ICNIRP maximum occupational exposure levels used in EU rules in the 10 GHz frequency range is 50 W/m^2.

    For the general public a lower level of 10 W/m^2 is used.

    For antennas commonly used in EME communication, power densities approaching these are only reached near the feedpoint or at open waveguides.

    Looking directly into an open X-band waveguide fed fed by 60 W average power may damage the eyes.

    73/
    Karl-Arne
    SM0AOM
     
  8. GM4BRB

    GM4BRB Ham Member QRZ Page

    I take it, without time to watch the vid, that we're also talking about microwaving a chicken.
    If you microwave a chicken, paley, you will almost certainly unravel it's protein structures, due high temperature H2O boiling under pressure in the meat, and render the thing to fattening stodge only. You may think you're enjoying a nutritious body-builders fayre but you are most likely chewing on unassimilable reduced proteins. You need your protein. Upto 50% of the protein consumed by a person is used to maintain the microtubule structures in the brain; energy greedy.

    An average build construction worker, doing an 8-hr shift may catalyse (from water, food and oxygen, also sunlight), upto 50% of her/his body mass in ATP, Adenosine Triphosphate, in a single shift. So my guess is that you need effective and traditionally cooked protein intake for maintaining your own health. Then we can think about your planned return to the moon. In this present condition, however, I regret, neither at 10Ghz nor 1 bike ride per decade, are we going anywhere.
     
    Last edited: Sep 30, 2019
  9. GM4BRB

    GM4BRB Ham Member QRZ Page

    60W? No, no no.
    Lower your eyes.
    I was advised 10mW even, may be enough to induce the first signs of a cataract.
    Though the amateur that thus advised me, was being extremely over cautious, I believe.
    Best advice however: And it's my bespoke advice. I live by it; I'd expect any sensible person to.

    "Never, under any circumstances, gaze into any apertures of a powered waveguide."

    The fundamental mode, or any god-damn mode in waveguide creates a concentrated source of em.
    The arrival of techniques for eye-replacement surgery are I believe, still at some considerable distance?
     
    Last edited: Sep 30, 2019
    AK5B and K0UO like this.
  10. VK7HH

    VK7HH Ham Member QRZ Page

    Also for clarification, the gun scope on the dish does not look directly into or near the feed, the dish also has mesh across this portion of where the scope looks through and care is taken to use it when not transmitting.
     

Share This Page