In P powered Ham radio the DC is supplied out to the antenna and RF generated locally - extremely efficient and no need for shielding as you are essentially modulating the aerial and want it to radiate.
From: Jones Beene [mailto:jone...@pacbell.net] Sent: Thursday, January 20, 2011 1:07 PM To: vortex-l@eskimo.com Subject: EXTERNAL: [Vo]:Coax ? Did anyone who watched the video closely notice a coax cable coming from the black (actually blue) box? If there is no coax there is no RF, so this hypothesis could be dead in the water. Unfortunately the resolution is not very high on any of the stills - and I am not going to view the vids again. Jeff Morriss, who is an expert in these things tells me, based on what can be seen at the binding posts: "If one looks closely at the blue box one sees 5 pairs of 5-way binding posts connected to what appears to be 2-conductor cables. In an earlier B&W photo the electronics were contained in a wood box, and the cables appeared spliced at one point. Based on the electrical characteristics of the cable and connectors it is possible to draw some conclusions. The first is that the power is either DC or low frequency (< 1 MHz AC) at currents less than 10 Amps/pair. At higher frequencies coaxial cable and matched impedances are required to effectively deliver power to the load. As for frequencies in the GHz range there is no way. My guess is that he is using either 50 Hz AC or DC heaters. Other possibilities include 20-40 KHz ultrasound or induction heaters, but the transducers tend to be large.
