DSS-43, the 70m antenna at the Canberra Deep Space Communication Complex (CDSCC) is currently off-line while a new receiver is installed. DSS-43 is primarily used to transmit signals to, and receive signals from, spacecraft at 2.1 GHz (“S-band”) or 7.1 GHz (“X-band”), however it also has other receivers allowing it to do regular radio astronomy. The old 1.4 GHz (“L-band”) receiver was removed a couple of years ago, and during the present shutdown a new receiver is being installed. The photo above is the view looking down the corrugated feed horn in the lab. The corrugated feed horn design provides a wider bandwidth and smaller sidelobes and cross-polarization. The specifications for the feed horn required the frequency range to be at least 1420 MHz to 1720 MHz — covering the neutral hydrogen hyperfine line (1420 MHz) and the OH radical main and satellite lines — with a design goal of 1350 MHz to 1850 MHz. The new system also receives both senses of polarization simultaneously, unlike the old receiver which only received a single polarization. (Image credit: @CanberraDSN)