“Ham,” or amateur, radio is often considered a hobby.

But when disaster strikes, it becomes an indispensable tool.

Ham radio doesn’t rely on the infrastructure other modes of communication, like cellphones, need to function. Some equipment can be powered by just a car battery.

When Hurricane Maria landed in Puerto Rico — wiping out nearly all of the country’s communication systems — the responsibility of getting messages on and off the island fell to amateur radio operators.

“When all else fails — ham radio,” Eric Bott, interim president of Carbon County Amateur Radio Club, said.

Last weekend, the American Radio Relay League held its annual field day — a countrywide event where ham radio operators from Seattle to New Jersey take to the airwaves to connect with their fellow enthusiasts. Field day started promptly at 2 p.m. on Saturday. It lasted until 2 p.m. Sunday.

The Tamaqua Wireless Association also had its annual field day exercise on Saturday and Sunday at Schroeder’s Family Tree Farm in Tuscarora.

Some operators made their contacts verbally, but other members — who were slated to start their shifts Saturday evening — transmitted their messages via Morse code.

The group’s goal was not only to make as many connections as possible over field day’s 24-hour period. It was to make sure that if an emergency did arise, they would be able to do their job, Glenn Schnell, who has been a ham radio operator for over a year, said. “We’re the last resort,” he said.

The club organized under the pavilion in Penn Forest Recreational Park.

They draped tarps over two sides of the structure — an attempt to keep the wind from interfering with communications. They also installed three antennas — two on the roof of the pavilion and one in the trees.

The club used three computers to log the contacts they made. The same log was used on the desktops, so each contact recorded was cross-referenced to avoid duplicates. But they had a rough start. The frequency bands were packed with fellow amateur radioists trying to connect. Bott repeated the club’s call sign, “whiskey, three, hotel, alpha,” over the microphone again and again.

Then he finally got response. An operator from Tennessee replied with his own call sign; “victor, echo, four, alpha, romeo, mike,” he called back. Some consider ham radio just a fun way to pass the time. Others, like Larry Dusablon, think of it as a way to serve the community.

“Anything we can do to be ready to help, we do,” Dusablon said.

Dusablon has been a licensed ham radio operator for about four years. His interest in radio started when he was a kid, after he built one from wire and cardboard for Boy Scouts. It wasn’t until Dusablon retired that he was able to finally delve into ham radio.

Dusablon noted that while not all emergencies pose equal threats, amateur radio operators are always at work in the midst of disaster. “The events that are more local don’t get as much headlines, but that doesn’t mean that the people who do ham radio aren’t there augmenting the communication,” he said.