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20 June 2021. San Jose, CA. This unusual (possibly unique) Brutalist-style concrete tower was built in 1972 as relay station on the former AT&T Long Lines Terrestrial Microwave network, and is currently used to host cellular telephone and land-mobile base stations (I believe leased to American Tower). Note that the 114 foot tower tapers slightly toward the top, giving the the illusion of greater height when viewed from ground level. Equipment was housed in a semi-hardened bunker below ground and adjacent to the tower. The site was also used as part of the Long Lines L-Carrier buried coaxial cable network. Note the large KS-15676 horn reflector antennas at the corners of the second level from the top. These antennas were mainstays of the Long Lines domestic network and could be seen on hilltop towers dotting the American landscape from coast-to-coast during the mid- and late- 20th century. KS-15676 horns are quite remarkable, both visually and technically. They can operate on multiple microwave bands with > 40dB return loss and have enough side isolation that relay stations could repeat on the same frequencies in different directions for receive and transmit with adjacent antennas on the same tower. At “hardened” facilities, the antennas could be equipped with “blast kits” designed (aspirationally) to withstand the pressure wave from a nearby nuclear explosion. A version of this antenna design (mounted on its side) was used as a radio telescope to make Penzias and Wilson's Nobel Prize-winning "big bang" background radiation measurements. The Long Lines Terrestrial Microwave network was decommissioned decades ago, but you can still find a fair number of vestigial KS-15676 horn antennas atop telephone buildings and towers from that era; there is often no safe and economical way to remove them. They measure 20 feet in height (from the top of the horn to the waveguide connection), 11 feet across at the top, and weigh approximately 3500 lbs. Tower structures were often constructed around them. Here, the original horn antennas have been removed from the topmost platform (and replaced with cellular telephone equipment), but they remain in place (with their waveguides disconnected) on the next lower platform. Rodenstock 50mm/4.0 HR Digaron-W lens (@ f/4.5), Cambo WRS-1600 camera, Phase One IQ4 150 digital back (@ ISO 50). 1/250 sec exposure. No emulsions were harmed in the making if this image. 002870