What if all Al needed to do was listen?
Her first project was cobbled together from books she borrowed from the communications people at Central Headquarters and a broken radio that her upstairs neighbor had thrown away.
It failed -- she couldn't even get static. Maybe because she dropped it climbing up to the roof.
Her next plan was to enlist the help of Winry, who, at the least, wasn't clumsy and was a competent electrician. Most automail engineers had to be, to turn nerve impulses into mechanical signals to move arms and legs. Through letters, she and Winry agreed Risembool would be a better site than Sheska's roof, since there was less short-range radio traffic. While Sheska arranged for her visit out to the sleepy town, she ran to stores she didn't know existed with lists from Winry of what they'd need for it that had to be found in the city.
The day before her train ride, she crammed the supplies and her magazine article into her trunk, spending nearly an hour to find the best fit. She didn't want things moving around, and everything had to fit into her small trunk. Eventually, she even could throw in some books for the trip back with the parts.
A half-hour before she left for the train station, she realized she hadn't packed any clothing, and quickly grabbed the laundry basket and emptied it into her suitcase. Half of the laundry ended up on the floor and she hoped that the stuff that made it in would have enough underwear for the trip.
Winry had asked Alphonse to help her with parts scavenging, because scrap metal and broken electronics were a lot easier to get than state-of-the-art equipment. The field outside the Rockbells' clinic became a maze of wires and metal supports, which puzzled the visitors to Grandma Pinako's clinic. While Winry was helping her grandmother, she could see Al checking things through the window. After coming outside one night to tell him to haul his butt indoors since a storm was coming, she caught him sitting next to the half-finished antennae, looking at the flickering thunderheads.
"Winry?" he asked.
"Sheska thinks this thing will let her hear alien radio, right?"
Winry nodded. She had mostly taken it on as an interesting practice project while she was visiting home on a break from her apprenticeship.
"If we find the right frequency, do you think it could pick up radio waves from the other side of the Gate?"
Winry didn't reply, and neither didn't mention that in the morning. But she could feel it lurking in the back of her head when the three of them put the final touches on the antennae, and hooked it up to a charter.
Sheska studied the printouts. "What do you think an alien signal would look like?" she asked.
"You mean you had us build this thing and you don't know?" Winry replied from the spot where she was positioning something.
"I thought we could just hook up a speaker and listen."
"The carrier waves are stronger than the ones containing information," Alphonse said softly. "And we don't know if it's amplitude or frequency modulation. So we just need to look for a spike that rises at the same time as a star."
Sheska paused. "That's going to take a while, isn't it? There's a lot of stars."
Winry looked at Alphonse. "We better make up some more paper for the charter."
She had brought a stargazing book with her, luckily. Sheska started pinning their tracks up, cutting each after twenty-three hours, fifty-six minutes and lining them up. Alphonse would often stare at them, marking things with a red pencil, and writing down coordinates after he had read the astronomy book.
"Sheska, what's at seventeen hours, forty-five minutes right ascension?"
Sheska looked at her stargazing book. "Vega. And the center of the Galaxy. Vega's a close by star. Is it aliens?"
Alphonse shook his head. "It doesn't look like what happens when the local station broadcasts. More like just fuzzy stuff. What else makes radio waves?"
"Thunderstorms," Winry suggested. "Moving electrons." They had learned a lot in the two days of bad weather which had been spent inside watching rain fall and doing work to help Pinako around the house.
"But there are no thunderstorms in space," Sheska replied. "Maybe we should ask at the university."
They contacted a university professor and ended up handed over their data when he seemed excited about this new discovery. He talked to Winry and Al about how they built their antennae, which lead to an exchange of letters that ended up in a cumbersomely-titled paper in the Amestrian Journal of Astronomy with all three of their names on it.
There had been a flurry of interest in the press, since Al was Ed's brother. Talk of prodigies running in the family, that the legendary Youngest State Alchemist Ever's little brother had produced an amazing new astronomical discovery -- it kept the papers' interest until some new scandal happened.
They didn't keep the telescope. Winry had donated it to the university, and the three of them carefully disassembled it so that students could move it to a location closer to Central.
Sheska was kind of disappointed. Science was exciting, but they didn't find any aliens.
Winry and Al were disappointed too, for their own reasons. Winry would occasionally catch Al after the fact looking at the southern sky, eyes following the Galaxy, as if the Milky Way was the path to the Gate.
Even on the other side of the Gate, Alphonse and Edward spent a lot of time in libraries. It was here that he happened on a magazine article about astronomy noting that the unit of flux density used in astronomy was the Janksy, after the discoverer of the galactic radio emission. He wondered, if they had gone home, would they find out that the unit was the Elric.