Mike, Wes raises one of the many interesting aspects of balun design, and not surprisingly, one that there doesn't appear to be a consensus on. Two of the main trade offs are bandwidth and choking impedance. The highest choking BW is usually obtain with an air core choke (coax looped with or without some form like PVC). However, this approach is very high Q, which yields relatively low R and narrow BW. I recently tested on of these that was centered at 14 MHz (by adjusting the number of turns and loop diameter) and the BW was only around 2-3 MHz. At the other end of the design spectrum is the sleeve balun, which has a very broad BW (1-30 MHz), but it has a relatively low impedance, which is almost entirely resistive.
Some say to go for the maximum reactance and minimum resistance, others say go for a net impedance of greater than 1K (or 5K depending on the "expert). Then there is also the issue of power dissipation which I haven't even touched on. So, which balun type you need is driven by what you want the balun to do. Feel free to contact me off line if you would like some more details. Bill N0CU -- View this message in context: http://elecraft.365791.n2.nabble.com/Choking-KPA500-and-testing-a-box-of-unknown-chokes-tp7631010p7631074.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
