The legacy 20m VLBI antenna at KPGO will undergo a major refurbishment later this year. The procedure involves lifting the main reflector off its bearing. The time lapsed video below shows what was involved in lifting the much smaller 12 meter reflector back in October 2015. In the next few months, the 20 meter reflector will be lifted as well using mechanisms to enable a life extending bearing replacement.

The bearing replacement will change the antenna "reference" location that has been established by VLBI over the past decade. It is vital that we do not lose continuity at the site, so in addition to the precise ground survey that was performed earlier this year, we are making a series of "short-baseline" VLBI observations using both the old and the new antennas at KPGO to establish the tie between these two antennas. These observations will also be an excellent test of the "mixed mode" technique that makes the broadband and the legacy S/X networks compatible. The continuity of geodetic legacy and broadband network locations at KPGO can then be re-established after the bearing replacement with verifiable before and after tests.