All of the talk of homebrew masers on time-nuts lately made me curious about the feasibility of a homebrew Josephson-junction voltage standard. It would seem that there are two large stumbling blocks: the junction array itself and the liquid helium temperatures. Is it at all possible to create the array at home or purchase one for a reasonable sum? Has there been any recent developments that allow for operation at higher temperatures (say, using liquid nitrogen that one might have a chance at using (or making: http://benkrasnow.blogspot.com/2008/08/diy-liquid-nitrogen-generator.html) at home)? Randy.