Complex sentence: From its beginning in the early 1930s, the LFR was augmented with Low Frequency Non-directional beacons (NDBs), which were simple, single-antenna transmitters, whose radio emission pattern was uniform in all directions in the horizontal plane.
Split into simpler sentences: From its beginning in the early 1930s, the LFR was augmented with Low Frequency Non-directional beacons (NDBs). NDBs were simple, single-antenna transmitters, whose radio emission pattern was uniform in all directions in the horizontal plane.