The only signal they're transmitting now is of their own presence on the ship.

The only clear, constant signal was pain hammering at the back of her skull.

It was the only signal I picked up clearly.

One word from Bayruth was the only signal they needed to cut loose.

"It was the only signal I could think of to tell you the road was mined ahead."

"Follow the leader" was the only reliable signal in a battle like this.

The only signals used were the spotlight and the green laser.

The approach to the station, from the south, was the site of the only signal on the line.

The only signal was the resumption of the elevator's progress up the building's face.

Lamplight touched the small lines around her eyes, almost the only signal that she was forty.