The instrument that typically sends a warning signal of approaching enemy troops is a sentry or lookout system, often using signal flares or alarms. In modern military contexts, this can also include electronic surveillance systems, radar, or unmanned aerial vehicles (UAVs) equipped with sensors. These systems are designed to detect and alert forces to potential threats in the vicinity. Overall, the key is to have an effective detection and communication mechanism in place for timely warnings.
Tuba is the straight trumpet. The curved trumpet used by the military to signal orders, etc. was called a "bucina" and was blown by a bucinator.
Paul Revere
Crickets were issued to parachute troops on D-Day. These were to be used as a recognition signal.
notified colonists of the approach of British troops
notified colonists of the approach of British troops
Aerophone
Aerophone
Aerophone
On the ground
Redcoats
Redcoats
This saying refers to a signal used by Paul Revere during the American Revolution to warn of the approach of British troops. "One if by land, and two if by sea" instructed that one lantern lit in the Old North Church meant British troops were advancing by land, while two lanterns meant they were approaching by sea.