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As aircraft started to be used against ground targets on the battlefield, the AA guns could not be traversed quickly enough at close targets and, being relatively few, were not always in the right place (and were often unpopular with other troops), so changed positions frequently. Soon the forces were adding various machine-gun based weapons mounted on poles. These short-range weapons proved more deadly, and the "Red Baron" is believed to have been shot down by an anti-aircraft Vickers machine gun. When the war ended, it was clear that the increasing capabilities of aircraft would require better means of acquiring targets and aiming at them. Nevertheless, a pattern had been set: anti-aircraft weapons would be based around heavy weapons attacking high-altitude targets and lighter weapons for use when they came to lower altitudes.

What was mounted on poles by forces?
machine-gun based weapons