1 rich Libsyn https://www.libsyn.com 90 600 In this episode, Grayson Evans, KJ7UM, joins us again to talk about designing and building ham radio gear with tubes, or as he refers to them: thermatrons.&amp;nbsp; Grayson is the author of Hollow-State Design, a book all about tube-type radio equipment.&amp;nbsp; Grayson also provides basic tube radio kits. Grayson is a great mentor and shares his love for all things thermatron ! Ham Radio Workbench Podcast http://hamradioworkbench.com/ <iframe title="Libsyn Player" style="border: none" src="//html5-player.libsyn.com/embed/episode/id/40040140/height/90/theme/custom/thumbnail/yes/direction/forward/render-playlist/no/custom-color/88AA3C/" height="90" width="600" scrolling="no" allowfullscreen webkitallowfullscreen mozallowfullscreen oallowfullscreen msallowfullscreen></iframe> https://assets.libsyn.com/secure/item/40040140