Profile

Browse more profiles
E.T. Revisited: Experiments in Transmission
E.T. Revisited: Experiments in Transmission

Thirty years ago, electrical and computer engineering professor Richard Campbell was a young physicist at Bell Labs. Every day he’d meet up with colleagues at the lunch table to share a love for amateur radio and imaginative thinking. “The culture was pure Bell Labs—eat lunch, chat with your friends, ask interesting questions and kick around ideas—the more entertaining the better,” recalls Campbell. “Those lunch table discussions were a highlight of my early career at Bell Labs.”

It was at one of these sessions that colleague Henry Feinberg, a self-described “interpreter of science and technology,” painted this scenario: Suppose an Extra Terrestrial needed to assemble a communications device from common hardware and bits of electronics. What would it look like? Drawing from many of these discussions, Feinberg would ultimately create the actual on-screen apparatus assembled by E.T. from household junk to phone home in the Steven Spielberg classic.

To cultivate an equally exciting and experimental intellectual culture at Maseeh College, Campbell proposed a similar hypothetical to his students in ECE 410/510 Instrumentation and Sensing: You are lost at sea. All electrical systems on your autonomous marine vehicle have failed. The battery on your Iridium satellite phone has been dead for days. You have no internet access. The one thing you have is a single solar cell from an LED yard light. Can you find a way to transmit a signal that could be recovered a thousand miles away?

As this was part of an upper division engineering class, Campbell’s students were expected to produce a functional prototype, not just something that would look good on screen. Faithful to the lost at sea scenario, they were also required to adhere to the following constraints:

  • The project cannot be plugged into a wall
  • It cannot connect to the internet
  • The total cost be less than that of a textbook (around $240)

Campbell's Instrumentation and Sensing graduate courses focus on rapid design, prototyping, and deployment—from white board sketches to deployable working hardware in only nine weeks. Early prototypes were quick and dirty, but functional:

Version two, built in the PSU Electronics Prototype Lab, was a little more attractive:

The class continued to iterate on their designs and produced several different prototypes for each task. By the eighth week of the quarter, they had enough hardware to assemble several complete systems and test them on campus over a 100 meter path. While the beacon prototypes proved successful over a short distance, success over a much greater distance remained inconclusive.

Once emitted, an electromagnetic wave bounces off of the upper reaches of Earth’s atmosphere in order to travel a long distance. This is called ionospheric reflection. Using power equal to that of an LED garden light, would the signal even have enough strength to perform this acrobatic feat and be recovered by someone very far away?

Student Ken Kimura set up a complete system at his home in Hillsboro, and transmitted the message “KE7XA PDX” starting in early December. With 35 milliwatts of output power the data rate took nearly 20 minutes to transmit this short message. He set this up to run continuously 24 hours a day, seven days a week.

A cooperating experimental station in Seattle was the first to positively identify the PDX signal, the third encoded vertical line in from the left:

Soon afterward, the signal was picked up by a receiving station in Corvallis. With a relatively minor improvement to the transmitting antenna, the signal was soon identified at New Mexico State University in Las Cruces, and then in Alaska near the now famous small town of Wasila. By early January, the signal was received in Florida. Satisfied with the results, they took the transmitter off the air soon afterwards.

The most important aspect of the Campbell's program at PSU isn't impressive hardware or off-grid electronic systems; it is a revival of the Bell Labs lunch table culture. In recent years, Maseeh College’s electrical and computer engineering department has invested a great deal of energy to develop a community that supports experimentation, and fearless inquiry while providing lab space, tools and materials to turn seemingly unusual ideas into working hardware.

“When I walked through the Engineering Building a few years ago, many of the labs were dark,” recalls Campbell. “I walked into Ren Su's office with ECE Department head James McNames and said ‘let's change that.’"