Progress toward improved water vapour radiometry: an overview of the South Africa-Mexico Bilateral Programme

Water vapour radiometers (WVRs) are critical to both site surveying and site management in microwave and mm-wave very long baseline interferometry (VLBI). We report on the first two years of progress made towards improving the state of water vapour radiometry at HartRAO, South Africa, and the LMT in Mexico, under a SAMexico bilateral programme. We report on progress in the development of low-cost site surveying instruments, multi-purpose cooled receivers, as well as refurbishment and upgrades to existing 22/31 GHz and 215 GHz tipping radiometers.