SDR: Software Defined Radio

A minimal setup: Raspberry Pi, RTL-SDR USB stick, dipole antenna

I’m using SDRs to receive telemetry data from satellites satnogs, track airplanes piware, weather balloons habhub, and vehicles aprs.

Getting Started

The best way to begin is to read the articles on RTL-SDR.COM and order their RTL-SDR V3 USB Dongle with Dipole Antenna Kit from Amazon for $35.00. Details on their website here, but they prefer US customers to order on Amazon.

You can use any modern computer with a USB port, but much of the open source SDR software is written for Linux. I recommend the use of a Raspberry Pi 4 with a 32GB SD card.

July 2020

I want to use SDRs in the classroom since they are easy to use and adaptable to many different topics. In the process of developing my lesson plans, I was pleased to discover the lab exercises in Stanford University’s EE 179: Analog and Digital Communications Systems class use the RTL-SDR. While the course content is much more technical than necessary for my target students, the labs (minus the Mathlab parts) can be successful executed by almost anyone with basic computer skills: https://web.stanford.edu/class/ee179/Homework.html

However, if you are interested in understanding the inner workings of signal processing, modulation and encoding, check out the lecture notes: https://web.stanford.edu/class/ee179/Notes.html

Signal Identification Guide: SIGIDWIKI.com and Artemis 3

If you ever wanted to identify a strange waveform seen on your SDR program, SIGIDWIKI.com is the place to go. It contains 100’s of example audio files and waterfall images, most recorded by popular SDRs. Artemis 3 is a front end application, sorting signals into categories you can browse. You can read more about it […]

Excellent PowerPoint Presentation Illustrating LoRa Waveforms

I discovered the work of Matt Knight who created an open-source implementation of LoRa on GitHub. His research documentation includes a PowerPoint containing examples of LoRa RF waveforms and the best illustration of CHIRPs. Get the PowerPoint here. And a LoRa paper here.

LoRa/LoRaWAN video tutorials on YouTube

Robert Lie Mobilefish.com has created a series of 53 video tutorials on YouTube explaining LoRa & LoRaWAN. Most are short (<6 minutes) and well indexed, so you can quickly find topics of interest. Many illustrations and demonstrations of LoRa signals on SDR displays. Highly recommended. Complete playlist at https://www.youtube.com/playlist?list=PLmL13yqb6OxdeOi97EvI8QeO8o-PqeQ0g He also published documentation and slides […]

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