The Bromley and District Amateur Radio Society

Bouncing signals off the moon
by Anchorage Daily News

Intresting Press article from the Anchorage Daily News (http://www.adn.com/)
______________

Mike Melum named his cat Eme after his hobby, though few people could guess what it means. The name, pronounced "Emmy," is an acronym for "earth, moon, earth."

EME is a complex feat of radio technology and astrophysics that Melum likes to do for the "huge rush." He sends radio signals into space from a 30-foot dish in his backyard. Other amateur radio enthusiasts pick up the signals he bounces off the moon. That's how Melum "talks" to people around the world, usually by Morse code but occasionally by speaking into a microphone.

It's an antiquated way of communicating with someone in, say, Japan. Indeed, Melum will sometimes use e-mail to schedule his earth-moon-earth communications. But EME is a kick for him and a few hundred others around the world who push the limits of their ham radios.

"That's what it's all about," said Melum, 56, of Anchorage. "It's like going to the moon. Why do you do it? Because you can. Or because you think you can."

They even have a name for themselves. They are "moon bouncers."


TALKING FROM THE MOON

It's a Sunday morning, and Melum's in the family room that's dedicated to radio equipment. He sits before a bank of buttons, gauges, digital readouts and an instrument for sending Morse code. He flips a switch here, cranks a dial there, intermittently tapping a Morse code message off into space.

A computer to his side shows a diagram of the moon's location over Earth. The moon's cycle brings it into view, and on this day it can also be seen in Sweden, where another moon bouncer has heard Melum's message. It's a man Melum knows best by his call sign, SM3AKW. Melum's is KL6M.

They exchange call signs -- which is protocol -- through a series of short and long beeps traveling roughly 476,000 miles to the moon and back to a single speaker. The conversation lasts about five minutes. They discuss the clarity of each other's signal, then trade niceties before signing off.

Growing up, Melum liked to tinker, fixing his mother's television, his grandmother's toaster. He and a friend modified their walkie-talkies to see if they could talk to each other from opposite ends of their hometown of Redfield, S.D.

The two of them built their first ham radios. Their instructions were whatever information they could glean from a Popular Electronics magazine. They used aluminum cake pans for the chassis and wrapped wire around toilet paper tubes for inductors. The radios worked. He was 15.

Melum didn't play with radios so much at South Dakota State University, where he earned a degree in electronic engineering. It was only after his job with the Federal Aviation Administration took him to Washington, D.C., that he started tinkering with radios again.

"I needed a release, some way to relax," Melum said. "I got into it (again) more for the socializing, picking up the radio and shooting the breeze."

Melum tried his first moon bounce in 1999, seven years after a transfer with the FAA brought him to Anchorage. He rigged up what is called a "Yagi" antenna, which looks like an oversized TV antenna that has grown clones of itself in every which direction. He made two EME contacts before the wind littered his yard with aluminum antenna parts. He made 50 contacts with his next Yagi setup.


ROOM FOR EVERYBODY

Moon bouncing is a "technology sport," said Allen Katz, who has been moon bouncing for more than 40 years.

Katz, 63, a professor of electronic engineering at The College of New Jersey, has published a newsletter since 1972 for moon bouncers, a niche market to say the least. He said moon bouncing attracts all kinds. A surgeon in Japan. A Nobel prize winner. A carpenter. College professors.

"People do it for the challenge," he said. "Why do people climb Mount McKinley? Because it's difficult."

He said Alaska generally has a large contingent of moon bouncers, naming four besides Melum. He estimated there are "maybe over 1,000" moon bouncers around the world. He thought Melum was operating among the top 250 or 300, the only one from Alaska performing at that level.

"I love the operating, to get on and make it work," Melum said. "But what I love more is making it better the next time I get on."

He started asking around about dishes. They are more efficient and simpler to maintain than Yagi setups, and they can be used for multiple radio- frequency bands.


HIS BABY HAS THREE LEGS

Melum needed more than Popular Electronics and a few household items to build his first EME system.

Four years after bringing home the 30-foot dish, he described the process of erecting it in an article he wrote for a magazine for amateur radio enthusiasts. He went into detail that only others like him could understand, but he added color that a layman can appreciate:

"The best find of all was in a junk yard behind a crane repair shop. I found a 30-inch, 300-pound bearing which had been removed due to failure to meet tolerance (but which had plenty for the dish). Two cases of beer later, it was in the back of my truck."

It took Melum about a year to develop and execute his plans for installing the dish. It rests on a 12-foot tower with three legs. The 30-foot diameter of the dish is twice that of any other operating in Anchorage that Melum knows of. The dish above Hooters restaurant is about as close in size to his as Melum could recall.

His tower has a 10-foot jackscrew that elevates the dish mechanically. The dish can stand at a full 90 degrees from its base, and it rotates 360 degrees.

The moon is a moving target, and Melum can hit it pretty much wherever it is above the Anchorage horizon. His aim has to be precise to bounce a signal off the moon, but he has the comfort of taking aim from inside his radio room.


REACHING OUT

Melum made 14 contacts Sunday morning in Texas, Australia, Austria, Canada, England, Sweden, Belgium, Colorado, Estonia, Norway, Germany and Estonia.

"That seems pretty good to me, just for a plain old weekend," he said.

To date, he's made contact moon bouncing with about 236 people in 30 countries as well as 28 states. He keeps notes of his contacts in a log.

Though Melum has been moon bouncing for nearly six years, there is room for improvement. For instance, he has to switch motors on and off manually to adjust the dish to follow the moon's path. He has designed computer hardware and software that will make the dish track the moon automatically, but he has yet to install it.

He figured he spends about 10 hours a week upgrading his system. "I'd like to spend 20 or 30," he said. "Then I might actually get somewhere."