FWIW: During the development of the E1938A, we tried replacing the foam insulation with a skeleton plastic frame with knife edges. The idea was that the plastic would have negligible heat conduction, leaving only air convection and radiation. We didn't see much difference between this set up and the regular foam, in terms of heater power. It also didn't make much difference with thermal gain.
Also, with both this oscillator and the 10811, different kinds of foam were tried. The general consensus was that all foams were more or less similar thermally, and the important characteristics differentiating them were mechanical (ability to not maintain shape after long exposure to oven temperatures) and various other manufacturing, supply chain, regulatory and environmental issues. Rick Karlquist N6RK _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
