Week 2

This week I continued my research on digital repeaters and software. I’ve decided to use a Raspberry Pi with the Pi-Star image, which contains software used to setup, configure, and maintain a digital repeater. It’s the most complete package I’ve seen and is widely recommended by other hams running digital repeaters. I have worked with this particular software package before so I have some understanding of how it works and how to use it. It basically contains many pieces of software which work together to manage and control a digital repeater. It can also be used to control digital multimode hotspots (duplex or simplex hotspots).

Pi-Star contains the popular digital radio software created by Jonathan Naylor, G4KLX: ircDDBGateway, DSTARRepeater, DMRGateway, and MMDVMHost. It also contains a complete dashboard and can support a wide variety of hardware. MMDVM stands for Multi Mode Digital Voice Modem.

The Raspberry Pi is a great piece of hardware for projects like this due to its cost, reliability, availability, and small size. I will be using the one I have already, a Pi 3B.

Capstone Project Proposal

For my capstone project, I want to build a digital multimode amateur radio repeater.

Amateur Radio is a two way radio service which in the United States is licensed by the Federal Communications Commission (FCC). It allows amateur radio operators the ability to talk to one another around the world using radio and to experiment with/design radio(s) and radio antennas. Amateur radio is often called “ham” radio. Ham radio is also used during natural disasters/emergencies to communicate when all other means of communication have failed.

I earned my Extra Class license about nine years ago. The Extra Class license is the highest license class that one can earn. While I’m not very active on the air talking to people, I enjoy the electronics and technology side of ham radio. More recently I have been working with digital repeaters, mainly Digital Smart Technology Amateur Radio (DSTAR) repeaters and occasionally Digital Mobile Radio (DMR) repeaters.

For my capstone I want to setup a multimode digital repeater that will switch between DSTAR and DMR depending on the signal it receives. This will be accomplished through the use of readily available software running on a Raspberry Pi that will be interfaced with a radio operating in the 70cm band.

The project will include a Nextion display to display information about the repeater and who is currently talking & allow one to control the repeater via touchscreen. I will design a screen layout for the Nextion display using Nextion Editor.

I will also add or enable a few extra features such as remote control through the ircDDBRemote app for DSTAR, remote SSH access, automatic linking based on a schedule, and possibly a few more as time permits.

I would like to learn how to design or modify and print a 3D printed case for my project too. 3D printing is something I have very limited experience with and would like to learn more about.