vitality00 Posted November 1, 2014 Posted November 1, 2014 The antenna's radio stations use to produce radio waves, can it be customized to emit radiowaves/gamma rays or if one simply increased frequency?
swansont Posted November 1, 2014 Posted November 1, 2014 The antenna's radio stations use to produce radio waves, can it be customized to emit radiowaves/gamma rays or if one simply increased frequency? Once you get to really high energy you are solidly in the realm of QM, so a simple radio antenna isn't going to work for this. Antennas are typically of order the length of the wavelength of the emitted radiation, because you want to drive a resonant circuit (you can have half- or quarter-wave antennas). And the circuitry to make such a circuit starts getting difficult long before you'd get to those wavelengths (From a semantic aspect, these would never be gammas, because technically they only come from nuclear interactions.)
Klaynos Posted November 1, 2014 Posted November 1, 2014 Parasitic losses limits the efficiencies of normal antenna as frequency increases. The limit kicks in around a few mm wavelength.
Sensei Posted November 1, 2014 Posted November 1, 2014 (edited) The antenna's radio stations use to produce radio waves, can it be customized to emit radiowaves You rather meant infra-red, as in title. Yes, you can emit infra-red photons from piece of metal through which we're passing current. No AC is needed, just DC. You should put metal with high resistance to vacuum (vacuum tube). With high enough voltage it will be emitting photons in visible spectrum (light bulb), at lower voltage black body emission will be shifted to invisible spectrum. But infra-red photons are easily absorbed. You can't transmit data similar way as using radiowaves for long distances (maybe in cosmic space). Do you have infra-red wireless mouse? Place hand between mouse and receiver, and it's no longer working. I have either radiowave wireless mouse and infra-red wireless mouse. Just checked - placed A4 thin piece of paper between IR mouse and receiver (5 cm distance between them). Mouse stopped working. gamma rays or if one simply increased frequency? Gamma rays from definition are emitted by radioactive/excited nucleus, or from annihilation of particle and its antiparticle. Edited November 1, 2014 by Sensei
studiot Posted November 1, 2014 Posted November 1, 2014 (edited) Hello, I don't know if your concern is safety That is can an ordinary antenna, designed for radio waves or even microwaves emit harmful radiation? Or are you hoping to generate such radiation using an antenna? Gamma radiation is the name given to natural radiation that is the result of nuclear processes. X radiation is radiation of the same frequency / wavelength that is artificially generated, but not using an antenna. Old fashioned vacuum tubes, particularly cathode ray tubes, produce (unwanted) X rays as part of the process within the tube. Out of interest here is a spectrum chart showing the relationship between various emissions, after the RSGB Radio Data Reference book. Edited November 1, 2014 by studiot
Externet Posted November 1, 2014 Posted November 1, 2014 Here is an infrared directional parabolic antenna; widely available at department and hardware stores : ----> http://images.palcdn.com/hlr-system/WebPhotos/84/843/8432/8432593.jpg?_v=5a94e708-b43a-47fc-b9d2-56110847a5a6
Janus Posted November 1, 2014 Posted November 1, 2014 The antenna's radio stations use to produce radio waves, can it be customized to emit radiowaves/gamma rays or if one simply increased frequency? One thing that has to be taken into consideration is the effects of capacitance and inductance when dealing with high frequencies. For example, even a 1 gauge wire would have a inductive reactance of hundred's of thousands of ohms per centimeter at just the far infrared frequencies and it would be a billion times greater at the gamma ray frequencies.
swansont Posted November 1, 2014 Posted November 1, 2014 Here is an infrared directional parabolic antenna; widely available at department and hardware stores : ----> http://images.palcdn.com/hlr-system/WebPhotos/84/843/8432/8432593.jpg?_v=5a94e708-b43a-47fc-b9d2-56110847a5a6 How do I dial in a particular frequency with that?
Enthalpy Posted November 5, 2014 Posted November 5, 2014 (edited) Yes, antennas exist for infrared and visible light, not for gamma wavelength. John D. Kraus proposed it very long ago. Presently, semiconductor technology can easily etch antennas of the proper length to resonate a µm wavelength and little below. Dielectric antennas work properly at visible frequencies. Metal antennas are bad, barely resonating because of big losses, but they do radiate and receive. The signal must be produced or used in the immediate vicinity because a metallic transmission line would loose power within µm; dielectric lines (for instance fibres), as opposed, are good. One example few years ago was a tiny semiconductor laser at ETH Zurich, smaller than a half-wavelength in each direction, that had a radiating resonating circuit instead of a cavity. http://phys.org/news188593304.html You noticed, this is all for very special purposes. Inconvenient for the general uses. Edited November 5, 2014 by Enthalpy
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