Mister Sparklord has ruled out some of the dumbest and easiest-to-catch ways that a master criminal could have set up the Distracting Surreal Element of the crime. Mister Sparklord notes for completeness that he's got some suggestive signs of the antenna not being totally a normal antenna anymore once you attach the backup shortwave radio to it, but it's hovering around the edges of what he can detect with improvised instruments. They're pushing things hard enough that a false positive would be almost expected. It's definitely not just that the backup shortwave was retuned to a different frequency along with the primary shortwave, that he's ruled out, but only a really lazy master criminal would've tried that in the first place.
(Somebody has now placed a bet that Mister Sparklord is actually the master criminal, here to watch his work play out, but it's only a small bet.)