Mentor guides engineering students as they construct amateur radios

Writer: Isabel A. Rodriguez

A group of NMSU electrical engineering students has succeeded in building ultra-low power radio transmitters that reach as far as Australia and New Zealand, with less than 200 milliwatts of power.

EE students

Electrical engineering seniors Stephen Arellano, Ciarra Villa and Daniel Cooper make adjustments to one of the amateur radios they custom-built, under the leadership of mentor David Hassall. (Photo by Isabel A. Rodriguez)

Working under the leadership of faculty adviser Robert Hull, Professor Vojin G. Oklobdzija and mentor David Hassall, the group is fulfilling a senior capstone project requirement.

Growing up in northern New Mexico, Hassall wanted to study engineering at NMSU after his stint in the U.S. Navy, but could not afford it. He is now achieving his goal of being part of the university community, through his work with the electrical engineering students. He and Oklobdzija met through their amateur radio activities.

“I immediately recognized the potential Hassall can bring to our students with his life-long experience in electronics, as well as long career as a communication officer in the U.S. Navy,” Oklobdzija said. “The most important challenge we face here is motivating our students. The reason for the lack of motivation is because the students do not see the applications and the value of the material we are teaching.


Dr. Oklobdzija shows off the ham radio he designed inside a tin Altoids can. (Photo by Isabel A. Rodriguez)

“I decided to bring Hassall in and start a very challenging project with the help of a group of enthusiastic students selected for this task. With this project, we are challenging everything they have learned.”

“All of the students were new to this,” Hassall said. “They had to obtain their Federal Communications Commission amateur radio licenses to operate the equipment.  This was uncharted territory for them, but they got it done, got their radios working. All four of them built their transmitters from scratch.”

Hassall’s FCC-issued call sign is WA5DJJ.

Stephen Arellano, electrical engineering senior, built his Manhattan-style ham radio for approximately $20. The model’s name refers to circuits built using glued-on, copper-clad pads.

The students followed the example of their mentor, who has a “why buy it when you can build it” attitude.

“I was always finding discarded electronics of every size and description on the street,” said Hassall. “They would end up in my little shop in the garage and get disassembled, all the parts carefully stored away for future use. With this supply of parts, building something was not that difficult, and I had to purchase very few extra parts. Even now, I am still scrounging parts.”

While most amateur radio stations use about 100 to 200 watts of power, the students’ transmitters use less than 200 milliwatts.

“Some (stations) go as high as 1,500 watts,” Oklobdzija said. “This is also the typical power that police, fire, marine and aircrafts use for communication, and they communicate on frequencies close to amateur radio bands. There is no commercial use (yet) for regular communication radios with this low power.”

Arellano explained that while ham radios can be used in numerous disciplines, the purpose of the project was to build a low-power transmitter that could reach the furthest distance.

“I think the most exciting part [of working on this project] would be the people behind it,” he said. “It’s interesting to talk to people from other countries – other ham radio enthusiasts from that community.”

After completing work on the transmitters, students will now construct the receivers, also known as “grabbing stations.”

“The project is getting more ambitious,” Oklobdzija said. “Our goal is to build a listening station that will, due to its unique features, put NMSU on the map of the world. We should not forget that NMSU is a historic site. This is the place where Ralph Goddard (NMSU founding engineering dean) built, in 1919, one of the very first radio transmitters in the world.

“We will be able to monitor the behavior and health of the ionosphere and link it with some unique phenomena that we are not able to explain. For example, when the solar-flare hit the Earth in May 2012, we knew it immediately because all of our signals shifted in a very strange way.”

This research has been pioneered by physicist, Joe Taylor, who earned a Nobel Prize while working on the Very Large Array radio telescope near Socorro, N.M. Taylor, an avid radio-amateur is a creator of a “Whisper Network,” a network of stations that transmit at the ultra-low power, below the noise level, Oklobdzija added.

“Building the grabbers will be more challenging, because we’ll have to use computer software,” said Ciarra Villa, electrical engineering senior.

Daniel Cooper and Thomas Buckner, also electrical engineering seniors, built their own ham radios, as well.

Hassall has more than 50 years of experience assembling ham radios.

“I have been interested in amateur radio all my life,” he said. “My mother said I got this way when I sat on a frayed electric light cord with a wet diaper, and she may be right. I built my first radio when I was about 9 or 10 years old. I have been an amateur radio operator for 53 of my 72 years.”

Hassall saidt the most challenging part of the process is learning to substitute parts one might not have access to.

“Most times, when you’re building from a magazine article, the author had access to many more parts than you do,” he said. “There will always be major parts that can’t be found. Learning to overcome that missing piece by building some kind of circuit to take its place is the most challenging part of building radio equipment.”

Hassall described ham radios as “this country’s greatest emergency radio communications systems.” They played a critical role during Hurricane Katrina and the Sept. 11 terrorist attacks, Oklobdzija added.

“Amateur radio operators responded with their equipment and provided needed communication when everything else failed,” he said. “Government and military rely on amateur radio operators for cases of national emergency, as there are many of them, and they are skilled to provide communication under very difficult and adverse conditions.”

“(During Hurricane Katrina), amateur operators used their own equipment and joined with others outside the disaster and started coordinating official and unofficial requests for aid,” Hassall agreed. “They also passed thousands of health and welfare messages for folks in and out of the disaster area, letting relatives know they were alive and needed assistance.”

“They can be called on at a moment’s notice,” he added. “Amateur communications networks can be organized ‘on the fly,’ as the conditions dictate. The United States has no other system that can do that effectively. In my lifetime, I have had the honor of doing some of these emergency operations. It is how I pay my country back for the enjoyment of being an amateur radio operator.”

To learn more about Hassall’s work, visit

CUTLINES: (Altoids) Dr. Oklobdzija shows off the ham radio he designed inside a tin Altoids can. (Photo by Isabel A. Rodriguez)
(Students) Electrical engineering seniors Stephen Arellano, Ciarra Villa and Daniel Cooper make adjustments to one of the amateur radios they custom-built, under the leadership of mentor David Hassall. . (Photo by Isabel A. Rodriguez)

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