I have the same question. The parallel wire feeder can pick up noise also by itself.
Bob K6UJ On Sep 29, 2012, at 11:10 AM, ab2tc wrote: > 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: > >> Elecraft@.qth > >> >> 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:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ 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
