Hi, So are you suggesting using a choke balun on both ends of the parallel wire feedline?
AB2TC - Knut Jim Brown-10 wrote > On 9/29/2012 5:40 AM, Barry, Stephen wrote: >> Does Elecraft have a balun solution for balanced feeders for the KAT500 >> at 500 watts? > > See the Choke Cookbook that is Chapter 8 in my RFI Tutorial, and the > discussion in the preceding pages, for an excellent common mode choke > that will satisfy this need. Use one of the chokes that is bifilar > wound with #12 THHN, connected as a parallel wire transmission line > between your parallel wire line and the tuner. > > http://audiosystemsgroup.com/RFI-Ham.pdf > > BTW -- the words "balanced feeders" and "balanced feedline" are pure > fiction. You will note that I used the words "parallel wire" to describe > the feedline. > > The balance of any system, including an antenna system, is defined equal > impedances to the reference plane. For antenna systems not on aircraft, > that reference plane is the earth, and the transmission line is only > part of that system. Most wire antennas that hams are able to erect are > unbalanced by their surroundings, which in turn causes the feedline to > be unbalanced. Imbalance in an antenna is caused by off-center feed, > ground slope, sloping wires, trees, buildings, even the varying ground > conductivity around the antenna. > > This imbalance will cause current on the feedline to become unbalanced, > which makes it part of the antenna. The feedline picks up noise and > couples it to the antenna (because it's part of the antenna). > > For this reason alone, smart hams have learned to use a common mode > choke at the feedpoint of an antenna This decouples the feedline from > the antenna, preventing noise pickup (and keeping RF out of the shack). > > 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto: > [email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html -- View this message in context: http://elecraft.365791.n2.nabble.com/Balanced-solution-for-KAT500-tuner-tp7563429p7563442.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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
