A cellphone antenna repairman was rescued early Wednesday after he slipped while working on a tower south of Cotati and became suspended about 50 feet in the air, firefighters said.

The man was working on the antenna resembling a farmhouse water tank near Old Redwood Highway at about 1 a.m. when he lost his footing in the fog, said Herb Wandel, battalion chief for the Rancho Adobe Fire Protection District.

He fell about 4 feet before his fall was broken by his harness, Wandel said.

The man hung upside down for a brief time and was righted by a co-worker, he said.

However, the co-worker was unable to get him down and the man remained hanging in the air for about 40 minutes, Wandel said.

Firefighters climbed the tower with their own ropes and rescued him, the battalion chief said.

The man, whose name was not available, was not hurt. Wandel believed he was a contractor for AT&T.

“He was a little shaken, but he was uninjured,” Wandel said.

Nine Rancho Adobe firefighters responded. They had been practicing rope rescue training earlier in the evening, just hours before the incident.

“The guys did a really good job,” he said