Complex sentence: Bowed decided to gain some familiarity with the equipment by building a ground-based transmitter in Bawdsey's Red Tower and the receiver in the White Tower, and found they were able to detect aircraft as far as away.
Split into simpler sentences: Bowed decided to gain some familiarity with the equipment by building a ground-based transmitter. Placing the transmitter in Bawdsey's Red Tower and the receiver in the White Tower, and found they were able to detect aircraft as far as away.