# SDR workshop
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**By the end of this lesson you will be able to**

- Understand what SDR is and what it can be used for.
- Listen to different radio frequencies using SDR devices and software.
- Explore different types of modulation and their effects on the received signal.
- Get basic information from airplane transponders and the International Space Station (ISS).
- Identify and understand different global navigation satellite systems (GNSS).
- Learn about SETI and the search for extraterrestrial intelligence.

**Learning objectives**
- Define what SDR is and how it differs from traditional radio communication.
- Learn how to connect an SDR USB device to a phone or laptop and use a "waterfall" SDR software.
- Understand the frequency ranges and modulation types used in FM radio, airplane transponders, and the ISS.
- Learn about CTCSS and its use in the ISS repeater.
- Explore different global navigation satellite systems and their frequencies.
- Understand the basics of SETI and its ongoing efforts to search for extraterrestrial life.

**Prerequisites**
- No previous knowledge or experience in radio communication or SDR is required. Basic computer skills and internet access are recommended.
- Software-defined radio (SDR) is a radio communication system where components that have been typically implemented in hardware (e.g., mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead implemented by means of software on a personal computer or embedded system.
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## Introduction
SDR technology enables radio designers to create more flexible, efficient, and cost-effective radio systems by utilizing the power of modern digital signal processing (DSP) techniques. With SDR, a single hardware platform can be used to support multiple radio technologies and standards, simply by changing the software that runs on it.

The concept of SDR has been around for several decades, but recent advances in processing power and hardware technology have made it more practical and accessible. Today, SDR technology is used in a wide range of applications, from military communications to public safety systems, to amateur radio and beyond.

### The basic elements of an SDR system include:
- An analog-to-digital converter (ADC) that converts the radio signal from an analog electrical signal into a digital signal that can be processed by software.
- A digital signal processor (DSP) that performs the necessary signal processing functions, such as filtering, demodulation, and decoding.
- Software that runs on the DSP and provides the user interface and control functions for the radio system.
- The use of software in SDR allows for a high degree of flexibility and customization, as well as the ability to implement new features and capabilities without the need for hardware modifications. SDR also enables the use of advanced signal processing algorithms, such as adaptive filtering and digital beamforming, that can improve the performance of the radio system.

In summary, SDR is a radio communication system that replaces traditional hardware components with software, enabling greater flexibility, efficiency, and cost-effectiveness. It has become increasingly popular in recent years due to advances in processing power and hardware technology. The basic elements of an SDR system include an ADC, a DSP, and software that provides the user interface and control functions for the radio system.

## Getting started with SDR

### Software

### Materials

### Setup

# Exercises
Learning goals for each exercise:

## A) Listen to local FM radio:
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Goals
- Understand the concept of software-defined radio (SDR) and how to use it to receive radio signals.
- Identify the frequency range of FM radio stations.
- Understand the concept of modulation and its effect on radio signals.
- Experiment with changing the modulation type and antenna to observe the changes in the received signal.
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**Instructions:**
- Connect your SDR usb device to your phone or laptop, and start any “waterfall” SDR software.
- Tune the frequency in between 88Mhz and 108Mhz
- Select proper modulation (FM)
- Try to change modulation and see what will happen.
- Try to play with antenna and see what will happen.

## B) Getting information from airplane transponders:
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**Goals:**
- Understand the concept of airplane transponders and their standard frequency.
- Install a scanner application to receive and decode the transponder signals.
- Understand the differences in transponder frequencies used in different regions.
- Explore the capabilities of the scanner application to identify information transmitted by the transponders.
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**Instructions**
To install “scanner” application look to the git
https://github.com/antirez/dump1090

- Android application also an option

## C) Listen to ISS:
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**Goals:**
- Identify the frequency of the downlink and uplink signals of the ISS.
- Understand the concept of CTCSS and its role in accessing the ISS repeater.
- Use the uplink frequency and access tone to access the ISS repeater and receive the downlink signal.
- Understand the basics of communication with satellites in orbit.
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**Instructions**
- Listening to the ISS is very easy: The frequency of the downlink is 145.80 MHz FM.

- Other option is to use ISS repeater, using an uplink frequency of 145.990 MHz with an access tone [CTCSS] of 67 Hz and a downlink frequency of 437.800 MHz

CTCSS – Continuous tone coded squelch system

## D) GNSS:
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**Goals**
- Understand the concept of Global Navigation Satellite Systems (GNSS) and their role in navigation.
- Identify the frequencies used by different GNSS systems and their respective satellites.
- Understand the differences between the various GNSS systems in terms of their coverage, number of satellites, and accuracy.
- Explore the capabilities of a GNSS receiver to obtain location information using signals from multiple satellites.
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**Instructions**

GPS (Global Positioning System) L1: 1575.42 MHz L2: 1227.60 MHz L3: 1381.05 MHz (being tested) (31 satellites, 24 for work)

GLONASS (Global Navigation Satellite System) L1: 1602.5625-1615.5 MHz L2: 1246.0-1256.0 MHz L3: 1202.025-1207.14 MHz (being tested) (27 satellites, 24 for fully operariona)

Galileo (European Union's Global Navigation Satellite System) E1: 1575.42 MHz E5a: 1176.45 MHz E5b: 1207.14 MHz E6: 1278.75 MHz (26 satellites, 24 for fully operational)

BeiDou (China's Navigation Satellite System) B1: 1561.098 MHz B2: 1207.14 MHz B3: 1268.52 MHz B1C: 1575.42 MHz (35 S, 24)

QZSS (Quasi-Zenith Satellite System) L1: 1575.42 MHz L2: 1227.60 MHz L5: 1176.45 MHz ( 4 S )

IRNSS / NavIC (Indian Regional Navigation Satellite System, Navigation with Indian Constellation) L5: 1176.45 MHz S: 2492.028 MHz (9 S, 7)

## E) SETI and Cosmos:
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Goals
- Understand the concept of the search for extraterrestrial intelligence (SETI) and its goals.
- Explore the SETI Institute's website and SETI@home project to learn about their research and initiatives.
- Understand the role of radio telescopes in the search for extraterrestrial signals.
- Understand the concept of the cosmos and its vastness in the universe.
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C) Listen to ISS

D) GNSS Global navigation is super present in last decade. There are several systems running, mostly politically defined.

E) SETI and Cosmos
https://www.seti.org/

https://setiathome.berkeley.edu/

https://www.seti.net/OriginalIdex.php

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