We continue with our great task of being able to analyze all those rays or radiations imperceptible to our natural optical systems (eyes), and thus continue structuring the essential and broad electromagnetic spectrum, where we have already known the ultraviolet rays, infrared, X-rays, microwave radiation, gamma rays, and this time we will know in general to radiation or radio waves.
We will do this by taking as our reference point the spectral portion of the light visible to our eyes, as we have done in the previous analyses, since as has been expressed through this spectrum we have managed to deepen the knowledge related to all the rays or radiations that make up the electromagnetic spectrum, demonstrating that these radiations impossible to see with our eyes are very essential in each of our daily activities.
In the previous article we were able to relate to the super energetic gamma rays, and this due to its reduced wavelength, and therefore, affecting this feature both in its frequency and of course in its large amount of energy, making these gamma rays in radiation called ionizing radiation for its high degree of penetrability in matter exceeding the X-rays or radiation.
It is important to point out that we will continue to be guided by the conceptualization of the luminous ray, whose propagation is rectilinear as geometric optics has provided us, and we will also continue with the link to our physical optics and its correct definition in terms of wavelengths, the latter, as we have already stated, establish the amount of energy that these rays or electromagnetic radiations have.
Taking into account our point of reference (white or visible light), we have moved from one side to the other of this spectral fraction, and thus on the left side of this reference spectrum we have found rays or radiations with wavelengths shorter than that of white or visible light, as is the case of ultraviolet rays, X-rays and gamma rays.
When we move to the right side of our spectral reference (white or visible light) the wavelengths are greater than this reference, and we have found the infrared rays, microwaves and in this opportunity we will analyze the radio waves, therefore, due to their wavelength they are imperceptible to human vision, but they are of immense utility in any type of development of living beings on this planet.
As we move away from the right band of our spectral reference we will find rays or radiations with less and less energetic capacity than the previous spectral portions, and therefore, with less energetic quantity than our visible spectrum, in this way it is possible to express that radiations or radio waves have a longer wavelength than microwaves, and these we can group in those non-ionizing radiations of our wide electromagnetic spectrum.
It is important to highlight that the main biological effect of radiofrequency electromagnetic radiations is heating, as we could observe in the analysis of microwaves and their application in ovens for heating some types of food, but as for the heating due to the exposure of these radiofrequency radiations to people, they are significantly lower, and so far no adverse consequences for our health have been proven, although it is a subject of constant analysis of these radiations due to the fact that as time goes by we are exposed to them in increasingly longer periods of time.
Throughout our rich history we have been able to use any type of knowledge extracted from our nature, and thus be able to generate artificial radiation for its implementation in any area of our development, as is the case of radio waves which are essential in the world of communication and have allowed us enormous advances in our modern lifestyle.
As it has been expressed, it is essential to take into account the important principle of physical optics which expresses that the vital phenomenon of light is a type of electromagnetic radiation and because of this we call it radiant energy, and in the same way we will use the fundamental principle of geometrical optics, that is, its light rays with rectilinear propagation.
Our referential spectral fraction (white or visible light) will serve to support us in this analysis of radio waves, these radiations are the least energetic of the electromagnetic spectrum, and therefore, we can say that they are much longer wavelength than our reference spectrum, and therefore, the amount of energy of a given radiation is inversely proportional to its wavelength, this leads us to say that radio waves have the longest wavelength but the least amount of energy of all the previously analyzed radiations.
According to the above, it is very clear that radio waves are radiations of the same nature as visible light, pointing out that they differ in their frequency or wavelengths and as we said, this characteristic makes them more or less energetic with respect to each other, and therefore, some are ionizing such as X-rays and gamma rays and others are non-ionizing such as ultraviolet, infrared, microwaves and radio waves.
No one could deny the great need that any person would feel if they did not have a device that implemented this type of radio waves in their home, for example, the device called radio and television, both instruments of great domestic necessity in our days, these devices or electrical instruments depend essentially on the radiations of radio waves to achieve their objective which is to transport some type of information either through a sound, an image or both at the same time as is the case of television.
Radio waves are effectively used as a means of transporting information since they provide essential advantages in this activity, such as: they do not require a physical medium to transport or transfer the required information, since, as stated in previous publications, electromagnetic waves can also propagate in a vacuum, including the speed with which this information can travel, since it travels at the speed of light, i.e., approximately 300,000 km/s.
Important characteristics mentioned above and offered by radio waves to the world that transports information, either by radio or television channels, however, these radio waves, in the same way as sound waves, attenuate as the distance traveled becomes greater, but this inconvenience can be minimized both by increasing the power of the generator of these waves and the sensitivity of the receivers designed to capture such waves.
We have been able to verify that the radio apparatus is an interesting technology which has been used for the transmission of signals through the conversion of the sound of the voice into electromagnetic waves or radiations, and the latter, as we said, do not need any physical means to propagate, these electromagnetic waves will travel after being emitted by a transmitting antenna until they reach an antenna or receiver, where these electromagnetic waves are converted into sounds that are derived from the initial voice.
If the radio system has been of great impact for all of us, I believe that the system implemented for the transmission and reception of both moving images and sounds at distances such as television, has been even more influential in our lives, such transmission of this system could be through radio waves of shorter wavelength than for the radio system itself, It is important to point out that there are other mechanisms for this type of joint transmission (moving images and sound) such as networks or cable television, however, our interest is focused on radio waves as electromagnetic radiation whose propagation is in the form of waves and rectilinear.
We will focus on radio and television signals transmitted by electromagnetic waves, which another of its great virtues is that they propagate at the speed of light, it is important to note that the transmission of these electromagnetic waves starting of course from a transmitting antenna to the receiving antenna could be by two ways or ways.
Therefore, one of these paths would be the direct transmission from the transmitting antenna to the receiving antenna of said waves, and the other way would be to reflect said transmission of waves in the ionosphere which, due to this reflection, return to reach our earth's crust, specifically to the receiving antenna of said reflected radio waves, as we can see in the following figure 1.
Figure 1. Transmission paths of radio waves
Important information as this could be very useful when carrying these radio waves which carry some information to another point that could be blocked by the curvature of our earth, and hence the essential to locate such antennas in very high places to provide greater effectiveness to the transmission and reception of such radio waves.
These types of communication transmission systems basically have two components, one called transmitter and the other receiver, the former being the originator of the electrical oscillations at a certain frequency called carrier frequency, the latter being transmitted in the antenna in the form of radiation or electromagnetic wave.
This irradiation or form of transmission is known as carrier wave, which when combined with the information to be transmitted becomes a modulated wave, which will propagate through space until it reaches the receiver, which must carry out a process known as demodulation in order to capture the information that was initially transmitted by means of a converter.
It is important to point out that the modulation method is originated due to the great interest of being able to carry or transport a certain information through our space, we will know in a general way this type of transmission method, and therefore, a carrier wave can be modulated in different ways and this will depend either on the amplitude or the frequency.
Amplitude modulation (AM) is a method that consists of varying the amplitude or intensity of a carrier wave in relation to the amplitude of the modulating wave, i.e. the amplitude of the carrier wave will vary according to the amplitude of the information to be propagated or transmitted, The representation of a carrier wave is shown in figure 2 below.
Figure 2. Representation of a carrier wave
Now you can observe a given carrier wave modulated according to its amplitude as shown in figure 3 below.
Figure 3. Amplitude modulated carrier wave (AM)
Regarding the frequency modulation we can clearly say that this method allows us to vary the frequency of the carrier wave in relation to the amplitude of the respective modulating wave, therefore, the frequency of the carrier wave will change according to the modulating wave, then we will show the representation of a frequency modulated wave in the following figure 4.
Figure 4. Frequency modulated wave (FM)
It is important to highlight that these modulation methods are widely implemented in the transmission of information, and the method that gives us the best quality in both sound and image is frequency modulation, the latter is implemented equally in mobile telephony as in television, taking into account that radio signals by amplitude modulation (AM) are implemented for transmission when distances are extensive and frequency modulated waves (FM) are used when the areas are less extensive.
Radio wave spectrum
As with the other electromagnetic radiations, in this opportunity we will continue with the conformation of the spectral fractions that make up the broad electromagnetic spectrum, therefore, in this opportunity we will add the spectral portion corresponding to radio waves, in this electromagnetic spectrum all these rays or radiations have been ordered according to their wavelength, and thus to their amount of energy or frequency.
The spectral portion of radio waves can be located or found after microwave radiations, that is, next to them, and because they are the lowest energy radiations that we have analyzed so far, they are at the top of the so-called non-ionizing or lower energy radiations of our broad and essential electromagnetic spectrum.
Remembering also that due to their longer wavelength in relation to our referential spectral portion (white or visible light) such radio waves or electromagnetic radiations are imperceptible to our natural optical instruments (eyes), and thus accompanying the other invisible radiations to our sight as ultraviolet rays, infrared, X-rays, microwaves and gamma rays, thus expanding the family of our electromagnetic spectrum as we can see in Figure 5 below.
Figure 5. Spectral Portion of Radio Waves
In the previous figure 5, we observe the spectral fraction of radio waves, whose wavelength is much greater than that of visible light, making these radiations imperceptible to our eyes, however, no one can deny the high impact that they have in the communication of any type of information either radio or television as you could see in the previous figure, and thus have been of great value in the development of our lives as we can see in the following figure 6.
Figure 6. Radio waves in our lives
With this article dedicated to radio waves, we continue structuring our electromagnetic spectrum, and thus highlighting the tireless work of mankind to interpret its natural environment and to extract from it any kind of learning that allows it to expand both its comfort and its longevity in this complex but wonderful universe.
So far we have been able to demonstrate that all the radiations already analyzed have great importance for the existence of all living species on this planet Earth, especially in the usefulness of radio waves in the world of communication, we know that it has been of enormous impact on our development in any area of our lives, This side of the spectrum in spite of being the radiation with the least amount of energy for its wavelength, they are very beneficial in the transition of any type of information, since they are electromagnetic waves and do not necessarily require a physical medium to propagate in a straight line as we have been taught by geometric optics.
Today we can affirm that thanks to technological advances these radio waves have managed to fit perfectly in this area, and in this way the development of applied science has been carried out in both radio and television signals, this leads us to highlight the essential task of the link between science-technology, and thus to ratify the conceptualization that expresses that technology is nothing more than applied science.
Until another installment my dear readers of Hive.blog, especially to the members of the great community of #Stemsocial, which receives the support of another wonderful community as #curie, so I highly recommend to be part of this exemplary project, as they allow us to highlight the wonderful work of academia and the enormous work of the entire field of science.
Note: All the images are of my authorship, made through Power Point, the animated gif were made through the application of PhotoScape.