This document provides instructions for receiving signals from ADS-B, AIS, and APRS systems using a software defined radio (SDR) on Ubuntu. It outlines the steps to install various software packages like dump1090, rtl-ais, gnuais, and multimon-ng. It also provides sample commands for decoding ADS-B transmissions on 1090MHz, AIS transmissions on 161.975/162.025MHz, and APRS signals on 144.640/431.040MHz using tools like dump1090, rtl_ais, gnuais, and multimon-ng in conjunction with the rtl-sdr SDR device.