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--- en:lesson01 [2020/03/25 16:03]
127.0.0.1 external edit
+++ en:lesson01 [2021/04/01 11:50] (current)
golikov
@@ Line 1: / Line 1: @@
-====== Receiving Radio Signals Using RTL-SDR======
+====== Receipt of radio signals using RTL-SDR ======
 ===== Frequency =====
-In Hertz, the number of oscillations per second is measured.
+The number of vibrations per second is measured in hertz.
-kHz = 1,000 Hz (one kilohertz - one thousand hertz)
+kHz = 1000 Hz (one kilohertz is one thousand hertz)
 MHz = 1,000 kHz = 1,000,000 Hz (one megahertz - one thousand kilohertz - one million hertz)
-GHz = 1,000 MHz = 1,000,000 kHz = 1,000,000,000 Hz (one gigahertz - one thousand megahertz)
+GHz = 1000 MHz = 1,000,000 kHz = 1,000,000,000 Hz (one gigahertz - one thousand megahertz)
 ===== Radio waves=====
 Radio waves - electromagnetic waves with frequencies up to 3 THz, propagating in space. Electromagnetic waves appear in the space around conductors with electric current. Radio waves are mainly used for organizing radio communications, for radiolocation, cooking, and sometimes for medical purposes.
-{{:en:image_14.png?600|}}
+{{:en:table_3.png?800|}}
+Meter and shorter radio waves are used to communicate with spacecraft units. Cubsat signals are mostly transmitted at the frequencies of 135 MHz and 433 MHz.
-Meter and shorter radio waves are used to communicate with spacecraft. The main frequencies at which we will receive signals from satellites 135MHz, 433MHz.
+We can use an RTL-SDR type radio to receive the signal. It is represented by a software-defined radio (SDR) - a radio station, in which the main part of digital signal processing is done by an ordinary personal computer.
-To receive the signal, we will use a RTL-SDR type radio.
+This makes it much cheaper and reduces radio station dimensions. Direct connection with a computer allows users to assess the received signal in a wide frequency band visually, as well as to learn such concepts as frequency, amplification, modulation, etc.
 {{:lesson01_02.png?200}}
-This type of receiver allows you to receive signals in the frequency range from 0.5 MHz to 1750 MHz.
+This type of receiver allows users to receive signals in the frequency range from 0.5 MHz to 1750 MHz.
 .5 MHz = 500 kHz = 500,000 Hz
-750 MHz = 1 750 000 kHz = 1 750 000 000 Hz
+,750 MHz = 1,750,000 kHz = 1,750,000,000 Hz
+RTL.SDR is based on the R820T2 chip, which is an analog signal converter, and RTL2832U chip, which is a digital signal converter completed with the USB interface.
-===== Introducing the SDR # program=====
+{{:en:table_4.png?600|}}
-Let's get acquainted with the capabilities of the SDR # program by receiving signals from FM radio stations. Run the SDR # program.
+The figure shows the block diagram of the RTL.SDR receiver. First, the R820T2 chip converts the analog signal into an intermediate frequency signal. Second, the intermediate frequency signal is transmitted to the analog-to-digital converter, which converts the incoming analog signal to the digital form (a flow of zeros and ones). The resulting signal is transferred via a USB connector to a computer for subsequent digital processing and output to the monitor. The most complex components of the superheterodyne receiver (filters and demodulators) are implemented in the digital form in the computer, which provides a cheap and more flexible solution.
-The controls are located on the left side of the window, and the spectrum of received signals in two forms is displayed on the right.
+===== Introduction to the SDR# software =====
+Let's get familiarize oneselves with capabilities of the SDR# software applied to receive signals from FM radio stations. Run the SDR# software. Control means are located on the left side of the window, and the spectrum of received signals provided in two forms is displayed on the right.
 {{:lesson01_03.png?600}}
-In the upper graph, the instantaneous signal strength is displayed along the vertical axis.
+The upper graph shows the instantaneous signal strength plotted along the vertical axis.
-At the bottom - power is displayed in brightness and color, and the time is plotted on the vertical axis. This graph is due to the characteristic
+At the bottom, the power values are described in terms of brightness and color, and time values are shown on the vertical axis. This graph is called "a waterfall".
-kind of frequencies called waterfall.
-The frequency of the received signals is plotted on the horizontal axis.
+The frequency of received signals is displayed on the horizontal axis.
+The first time a user launches the program, he/she shall select a corresponding radio type: RTL-SDR connected via USB.
-When you first start the program, you must select the type of radio: RTL-SDR connected via USB.
 {{:lesson01_04.png?200}}
-In the Radio section, set the switch to WFM mode and set the Bandwidth to 100000.
+Set the switch to the WFM mode and set the bandwidth to 100000 in the "Radio" section.
 {{:lesson01_05.png?200}}
-Set the frequency of reception, for example.
+Determine the receipt frequency.
 {{:lesson01_06.png?200}}
+If you are in Moscow, you will get a strong signal from the radio station using this frequency.
-If you are in Moscow, then at this frequency there will be a powerful signal from the radio station.
 {{:lesson01_07.png?600}}
-If you now increase the volume, you can hear the radio broadcast.
+If you turn up the volume, then you may hear certain radio transmission.
 {{:lesson01_08.png?200}}
+The graph clearly shows that there is another radio station broadcasting using the frequency 103.0 FM. You can change a layout of the graph using the sliders on the right edge of the screen.
-The graph clearly shows that at a frequency of 103.0 Fm another radio station is broadcasting.
-The appearance of the graph can be changed using the sliders located on the right border of the screen.
 {{:lesson01_09.png?200}}
+If you click on the frequency line and move it to the right or left, you can find other radio stations.
-If you click on the frequency line with the mouse, and move it to the right or left, then you can find other radio stations.
 {{:lesson01_10.png?400}}
+You need to increase the signal strength to receive weak signals. To do this - click on the gear icon.
-In order to receive weak signals, it is necessary to increase the signal gain. To do this, click on the gear.
 {{:lesson01_11.png?200}}
-Move the slider so that the noise level rises by about 10 dB.
+Move the slider so that the noise level increases by about 10 dB.
+{{:en:image_4.png?250|}}
-{{:lesson01_12.png?200}}
+{{:en:image_01.png?700|}}
-{{:lesson01_33.png?600}}
@@ Line 90: / Line 93: @@
-====Exercise 1.====
+==== Task 1. ====
-Move the frequency line and listen to all Fm radio stations.
+Move the frequency configuration line and listen to all Fm radio stations.
 ----
@@ Line 99: / Line 102: @@
 ===== Decibels. =====
-A decibel is a relative value that shows how many times one signal is more powerful than another.
+A decibel is a relative value which shows how many times one signal is stronger in comparison with another.
-dB - 1.25 times, 3 dB - 2 times, 10 dB - 10 times.
-When adding decibels, you need to multiply times:
+dB - 1.25 times, 3 dB - 2 times, and 10 dB - 10 times.
-dB = 3 dB + 3 dB (2 · 2 = 4 times)
+When adding the decibels value, a user needs to multiply the time value:
- dB = 3 dB + 3 dB + 3 dB (2 · 2 · 2 = 8 times)
+ dB = 3 dB + 3 dB (2 - 2 = 4 times)
- dB = 10 dB + 3 dB (10 · 2 = 20 times)
+ dB = 3 dB + 3 dB + 3 dB (2 - 2 - 2 = 8 times)
- dB = 10 dB + 10 dB (10 · 10 = 100 times)
+ dB = 10 dB + 3dB (10 - 2 = 20 times)
- dB = 10 dB + 10 dB + 10 dB (10 · 10 · 10 = 1000 times)
+ dB = 10 dB + 3 dB (10 - 2 = 100 times)
+dB = 10 dB + 10 dB + 10 dB (10 - 10 - 10 = 1000 times)
-===== Frequency ranges. =====
+===== Frequency bands. =====
-All radio frequencies are divided into several bands. Some frequency ranges are used for communication by the military and special services - civilians are prohibited from broadcasting in such ranges. But there are also “open” frequency ranges in which radio amateurs and civil organizations are allowed to work - air traffic controllers, railway workers, power engineers, etc.
+All radio frequencies are divided into several bands. Some bands are applied for military and special services communications - civilians are not allowed to broadcast in those bands. However, there are also "open" frequency bands in which radio amateurs and civilian organizations - air traffic controllers, railroad workers, power facility workers, etc. are allowed to operate. You will find the following frequency bands, color-coded in SDR#.
-You will find the following frequency ranges marked in color in the SDR #.
+Long wave band (LW).
-Range of long waves (LW).
 {{:lesson01_15.png?300}}
+Mid-wave band (MW).
-The range of medium waves (NE).
 {{:lesson01_16.png?800}}
+Shortwave band 160m (SW).
-Amateur shortwave range 160m (HF).
 {{:lesson01_17.png?300}}
+Shortwave band 80m (SW).
-Amateur radio wavelength range 80m (HF).
 {{:lesson01_18.png?400}}
+Shortwave band 40m (SW).
-Amateur shortwave range 40m (HF).
 {{:lesson01_19.png?200}}
+Shortwave band 20m (SW).
-Amateur shortwave range 20m (HF).
 {{:lesson01_20.png?300}}
+Shortwave band 15m (SW).
-Amateur Radio Shortwave Range 15m (HF).
 {{:lesson01_21.png?300}}
-The civilian range is 27MHz. (Citizen`s Band). All walkie-talkies operate in this range.
+Civil band 27 MHz. (Citizen`s Band). All radios operate in this range.
 {{:lesson01_22.png?300}}
+Shortwave band 10m (SW).
-Amateur shortwave range 10m (HF).
 {{:lesson01_23.png?300}}
+The frequency range of FM radio stations varies from 87.5 to 108 MHz (VHF)
-Frequency range of FM radio stations from 87.5 to 108 MHz
 {{:lesson01_24.png?300}}
-Frequency range of air traffic controllers from 108 to 137 MHz
+The frequency range of air traffic controller stations varies from 108 to 137 MHz (VHF)
 {{:lesson01_25.png?300}}
-Amateur Radio Band 144-148 MHz
+The amateur frequency range varies from 144 to 148 MHz (VHF)
 {{:lesson01_26.png?300}}
-The range of military frequencies is from 225 to 380 MHz.
+The military frequency range varies from 225 to 380 MHz (VHF)
 {{:lesson01_27.png?300}}
-Amateur radio range from 430 to 440 MHz
+The amateur frequency range varies from 430 to 440 MHz (VHF)
 {{:lesson01_28.png?300}}
@@ Line 188: / Line 181: @@
 ----
-==== Exercise 2. ====
+==== Task 2. ====
-Move the frequency line and find all ranges from 0 to 500 MHz.
+Move the frequency line and find all bands in the range from 0 to 500 MHz.
 ----
-===== Types of modulation. =====
+===== Modulation types. =====
-In order to improve the quality of the signal transmitted by radio, use modulation. Modulation is a special way to encode a signal. For example, all radio stations that broadcast in the FM band encode a signal in a special way called frequency modulation (English frequency modulation for FM).
+Modulation is used in order to improve the quality of a radio signal. Modulation is a special way of signal coding. For example, all radio stations which broadcast within the FM band encode the signal in a special way called frequency modulation (FM in English). The next popular modulation method is represented by amplitude modulation (AM in English). A continuous signal is used to transmit Morse code signals. Signals with different modulations appear to be different in the SDR# software.
-The next popular modulation method is amplitude modulation (AM amplitude abbreviation).
-To transmit Morse code signals, CW (Continuous Wave) modulation is used.
-Signals with different modulations look different in SDR #.
 ==== Frequency modulation.====
-Typical frequencies: ultrashort waves from 87.5 to 108 MHz
+Typical frequencies: ultra-short waves from 87.5 to 108 MHz
-The image of the signal.
+Signal imaging.
 {{:lesson01_29.png?200}}
 ==== Amplitude modulation.====
@@ Line 217: / Line 206: @@
 Long waves - from 153 to 279 kHz
-Medium Waves - 531 to 1.611 kHz
+Medium waves - from 531 to 279 kHz
 Short waves - from 2.3 to 26.1 MHz
-Negotiations of air traffic controllers - from 108 to 137 MHz
+Air traffic controllers' conversations - from 108 to 137 MHz
-The image of the signal.
+Signal imaging.
 {{:lesson01_30.png?200}}
-Typically, the SDR # program itself correctly determines the type of modulation characteristic of the radio wave band. Manual modulation can be switched in the Radio section. FM modulation is called WFM here.
+As a rule, the SDR# software itself determines the types of radio band modulation characteristics in a correct way. Manual modulation can be activated in the “Radio” menu. FM modulation is called WFM here.
 {{:lesson01_31.png?200}}
 ----
-==== Exercise 3. ====
+==== Task 3. ====
-Find the radio station in the FM band and switch modulation modes. Normal sound will be heard only with WFM modulation.
+Locate a radio station in the FM band and switch between modulation modes. A normal sound will only be heard using the WFM modulation.
 ----
-==== Exercise  4. ====
+==== Task 4. ====
-Find air traffic controller talks in the range of 108 to 137 MHz. Normal sound will be heard only with AM modulation.
+Find air traffic controllers using the range from 108 to 137 MHz. A normal sound will be heard only using the AM modulation.
 ----

"Viewnok" training station for satellite data receipt

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