Fans can use radio earphones at the U.S. Open to...

Fans can use radio earphones at the U.S. Open to listen to Cindy Shmerler hosting tournament coverage on AMEX radio. Credit: Getty Images (left), Neil Best (right)

Glenda Myles and Deedy Harris, visiting the U.S. Open from New Orleans, were sitting in the plaza outside of Arthur Ashe Stadium on Friday, cheering for Coco Gauff in her third-round match against Elina Svitolina.

Did they not have tickets for seats inside Ashe for the big match, in which Gauff came back to win after losing the first set?

“Yes, we do,” said Myles, who is Harris’ mother. “But here I can see three games at once [on video boards outside the stadium]. They give us a lot of information also. So it’s very exciting.”

The information to which Myles referred included the earpiece both women wore, which was attached to a light blue lanyard around their necks.

It is a small, ear-mounted radio that only works on or near the grounds of the Billie Jean King National Tennis Center and only carries American Express Radio, which allows fans to listen to ESPN’s live coverage of matches and provides additional tennis content at other times of day.

The lanyards might be the second-most common sight on the Open grounds, after the ubiquitous Honey Deuce cocktail, and it generates the second-longest lines.

But unlike the $23 Honey Deuce, the mini-radio is free. Free, but not for everyone. Only people who produce an American Express card are given one — only one per card.

It would appear there are many Open fans who have AMEX cards, because early in every day and night session throngs line up to get them.

By 9:45 a.m. on Friday, about 15 minutes after the gates opened, there were 75 people in line at the booth nearest the entrance.

Fans are not required to return the radios before leaving, but most do so in drop-off boxes provided, since they are useless outside the grounds.

This year, American Express ordered 140,000 radios for the week. The radios have been part of the Open since 2002.

“This will be our third year at the Open, and we’ve used them every year,” Harris said. “We can hear what’s going on all at once. You can get it all in your ear.”

When ESPN is in a commercial break, the show continues on AMEX radio.

Cindy Shmerler, a host for the station for eight years, watched the action from her perch high above the Ashe court and gave fans additional background information, directed them to noteworthy matches and interviewed fans.

Shmerler, a longtime journalist with an expertise in tennis, said she loves the job because of the storytelling opportunities — and the passionate listeners.

The station might only be heard at the tennis center, but that means a captive, hyper-focused listenership.

“It is a completely engaged audience,” Shmerler said. “They care, and they will correct you, so you will find out exactly what you’ve done wrong.”

Radios for on-site fans are even more important at golf tournaments, where the action is spread over vast areas.

But it helps in tennis, too, especially early in a tournament when a lot is going on. (It also helps when standing on long concession lines.)

During a break in the Gauff match, which drew a huge in-person audience, Shmerler was able to tip off interested fans outside the stadium to visit Court 12, where the retiring American Shelby Rogers was behind in her doubles match.

She encouraged people to head there and cheer Rogers on. (Rogers lost in straight sets.)

“If they feel like they can be listening and learning something while they’re watching,” Shmerler said, “my job is to tell them something they didn’t know an hour before, or 10 minutes before.”

Soon, fans attending the day shift would be depositing their radios and heading for the exits, and the night shift would arrive, lining up for their boxes, too.