In 1857 a signal mast was erected at Barker Knoll to convey safe passage condition messages to vessels wishing to pass through the mouth.

Captain Bitts and two sailors in oilskins were standing at the foot of a signal mast.

The sawmill also produced everything else such as signal masts and boxes, bridges, sleepers, and even furniture for railway stations.

"I thought that might do for the moment as a signal mast."

In 1909 the Signal School was established and three signal masts were erected.

She also had one Type 13 air search set installed with an antenna mounted on the signal mast above the bridge.

The telegraph line comprised 62 stations each furnished with a signal mast with six cable-operated arms.

The white, red, and green tricolor of Italy fluttered on the signal mast under the American flag.

This system provides train crews with information about the next signal indication, even if the signal mast is not visible.

A signal mast was erected in the sandhills at North Head in 1876, 5-6 miles west of the station.