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Gynkana atmosférica_antena yagi - Contenido educativo

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Subido el 20 de marzo de 2023 por Maria Jesús T.

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Introducción a la comunicación por radio en CanSat

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Welcome to CANSAT EVA! 00:00:01
Let's talk about radio communications and the Jaggi antenna. 00:00:11
Radio waves are all around us in our everyday life. 00:00:22
But what do we mean by a radio wave? 00:00:26
And how are radio waves important for your CANSAT mission? 00:00:30
Lots of our day-to-day communications rely on radio waves, perhaps things you wouldn't expect, such as Wi-Fi and Bluetooth. 00:00:36
Not just car radios. We will explore what exactly radio waves are and how we can use them to communicate with our concepts. 00:00:47
Radio communication is sending information from one place to another using a type of electromagnetic wave, radio waves. 00:01:02
As you can see here in the electromagnetic spectrum, radio waves are at the long wavelength end of the spectrum and, unlike sound, they can propagate in vacuum. 00:01:12
Let's explore the radio spectrum. 00:01:27
As you can see in the image, for satellite communications we use super high frequency 00:01:35
bands with frequencies ranging from 2 GHz to 30 GHz and wavelength ranging from 1 cm 00:01:41
to 10 cm, these waves fall within the microwave band. So radio waves of these particular frequencies 00:01:53
are called microwaves. In turn, we will work in the ultra-high frequency 00:02:03
event of this spectrum. We'll use either an APC220 transmitter, which works at 433MHz 00:02:10
approximately or a LoRa transmitter, which works at 868MHz. XB is commonly used in IoT, 00:02:23
but we will not consider it here, depending on the type of data that we want to transmit 00:02:36
and the distance, we will choose a different transmitter and a different frequency. 00:02:47
If you have a simple piece of data to transmit, such as a SOS signal, but over a significant 00:02:56
distance a low frequency so long wavelength is perfect however broadcasting video from a 00:03:05
concept to a ground station requires a much higher bit rate but over a much shorter distance so is a 00:03:15
higher frequency is preferred. How does radio communication work? 00:03:25
A transmitter creates an oscillating signal on a cable connected to the antenna. That signal 00:03:34
is transformed and emitted as electromagnetic waves through the antenna. At the receiving 00:03:43
end of the communication, part of this wave is collected and transformed back into electric 00:03:51
current by another antenna. The concept project will involve two antennas. The first is the antenna 00:03:58
on board the Gensat, a DAC antenna. The second is the antenna at the ground station, a Jackie antenna. 00:04:09
A DAC antenna is likely the type of antenna you are most familiar with because you will 00:04:17
find them on the back of your household routers or modem. 00:04:29
Inside the plastic casing of a DAC antenna is a metal helix. 00:04:37
This is used to receive or transmit the signal. 00:04:42
Another type of antenna you would be familiar with is the jaggy antenna. 00:04:48
This is the antenna that is often found connected to old-fashioned televisions and on the rooftops 00:04:53
that receive analog television signals. 00:05:03
Building a jaggy antenna for a concert is a good option, as it can be constructed relatively 00:05:06
easily using cheap materials such as wood and copper tubes. 00:05:14
Now we're gonna design our jaggy antenna using the KN9B Jaggy Antenna Calculator. 00:05:25
We're gonna fix the frequency under number of elements, let's say 433 MHz for a typical 00:05:33
APZ220 transmitter. 00:05:43
What about the number of elements? 00:05:46
One of the main factors affecting the jaggy antenna gain is the number of elements in 00:05:49
the design. 00:05:55
Typically, a reflector is the first element added in any jaggy design, as it gives the 00:05:56
most additional gain. 00:06:03
Directors are often added. 00:06:06
Element spacing is another factor that must be considered. 00:06:11
Spacing can have an impact on the jaggi gain, although not as much as the number of elements. 00:06:18
Finally, the antenna length. When computing the optimum position for the various elements, 00:06:27
it has been shown that in a multi-element jaggi array, the gain is generally proportional to the 00:06:34
length of the array. With 8 elements distributed according to these lengths, we can finally 00:06:42
design our jaggy antenna, with a gain of almost 11 decibels, which is a rather good value for a cancer. 00:06:53
Now it's time for our jaggy antenna challenge. This is a jaggy antenna that we have in Madrid 00:07:03
Science Fair. You have to put all the different parts of the antenna in order. Would you be able 00:07:13
to do it? Congratulations! You've done a great job! Please continue with our atmospheric gincana 00:07:21
too long to the rocket. 00:07:33
Idioma/s:
en
Autor/es:
María Tamés Esteban
Subido por:
Maria Jesús T.
Licencia:
Reconocimiento - No comercial - Compartir igual
Visualizaciones:
40
Fecha:
20 de marzo de 2023 - 8:52
Visibilidad:
Público
Enlace Relacionado:
https://esamultimedia.esa.int/docs/edu/T11_Radio_Communication.pdf
Centro:
IES PRINCIPE FELIPE
Duración:
07′ 53″
Relación de aspecto:
1.78:1
Resolución:
1920x1080 píxeles
Tamaño:
134.75 MBytes

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