T-Mobile proposes modifications at an existing monopole telecommunications facility located at an address 100 Armory Drive, San Francisco, San Francisco County, CA 94132 (37° 43' 37.80" N, 122° 30' 12.64" W). The existing monopole tower will be replaced with a new monopole that is the same overall height, approximately 54 feet tall. Support equipment will be routed to and installed within the existing equipment compound. Eocene Environmental Group is publishing this notice in accordance with Federal Communications Commission regulations (47 CFR § 1.1307) for Section 106 of the National Historic Preservation Act (NHPA) and for the National Environmental Policy Act (NEPA). Parties interested in commenting on this Federal undertaking or with questions on the facility should contact Eocene Attn: Telecommunications Department, 8951 Windsor Parkway, Johnston, IA 50131 or call 515-473-6256 (Ref. T-Mobile TriLA #2055-AM).