Complex sentence: The 689th Radar Squadron was originally assigned to the SAGE Portland Air Defense Sector (PoADS) at Adair Air Force Station, Oregon, a part of the 25th Air Division SAGE at McChord AFB, Washington.
Split into simpler sentences: The 689th Radar Squadron was originally assigned to the SAGE Portland Air Defense Sector at Adair Air Force Station, Oregon. Later it became part of the 25th Air Division SAGE at McChord AFB, Washington.