Stevens Seniors Develop SDR Amateur Radio Repeater

4/25/2012

For their Senior Design project, several Stevens students are developing a technology that extends the range of amateur radio signals. Erik Thompson, Dan Nowak, Scott Curtis and Jon Pirog are designing a software defined radio (SDR) repeater, on display at today's Stevens Innovation Expo.

A traditional amateur repeater is an electronic device that receives a weak amateur radio signal and then retransmits a more powerful signal, so the signal can cover farther distances. Made possible through advances in digital electronics, a SDR amateur repeater transmits signals through software, not hardware. It can be upgraded and maintained simply by refreshing computer software, meaning operators no longer need to purchase special-purpose hardware to improve functionality.

“The SDR amateur repeater is advantageous because of its re-configurability, which will ultimately save users both time and money,” Pirog said.

The team’s design consists of a repeater module to perform the repeating functions and a user interface to allow operators to remotely change repeater parameters, such as input and output frequencies, tone access modes and output power. They hope to complete a workable prototype in less than a year and plan to charge approximately $700 for their product, which is less costly than repeaters currently on the market.

Amateur radio operators are licensed for noncommercial use of the radio spectrum using modes of transmission such as Morse code, AM and FM1. These hobbyists typically use the radio for private recreation.

According to Thompson, the team’s project manager, Hoboken is the ideal place for an SDR amateur repeater to benefit the amateur radio community. He hopes the team’s SDR amateur repeater can ultimately be picked up by a local amateur radio club, for example.

“Amateur radio is ideal for urban setting, where there are so many large buildings and existing signals,” Thompson said.

He added that the technology could also be attractive to a college or university, which may include amateur radio hobbyists. In fact, that is how the idea for the project was born.

“I’ve been interested in amateur radio for years, and when I got to Stevens and realized that it didn’t have a repeater, I thought that that should change,” he said.

Beyond recreation, a potential use for a SDR amateur repeater is emergency response. Amateur radio can be an effective means of emergency communication when conventional, commercial means fail. For example, it was used during the September 11 attacks on the World Trade Center and Hurricane Katrina in 2005 to coordinate disaster relief efforts.

Having completed a highly-technical design plan, the team has spent countless lab hours developing its prototype, using knowledge of digital design, computer programming and radio frequency concepts to make the hardware and software systems work together.

“We really have to communicate in order to keep moving forward [with the project],” said Thompson. “Because everyone in the group has a very specific job, we constantly have to check to see where each member is with their work.”

The project is sponsored by International Telephone and Telegraph (ITT), which will allow the students to continue developing their design to completion.