Hi Jim, The FCP isolation transformer is not a balun. It does NOT have a common connection between the primary and secondary. It is NOT broadband, which is a specific goal of a balun. On the Balun Designs web page www.balundesigns.com it is listed as "FCP transformer." It is an RF transformer, and has residual inductive reactance that has to be tuned out in one way or another. In the simple inverted L plus isolation transformer plus FCP configuration, the left-over capacitive reactance from the FCP is roughly equal to the inductive reactance of the isolation transformer. Neither device is resonant by itself. They are resonant overall when used in tandem.
The FCP isolation transformer is specific to a single band. It takes extra switched in/out tuning network circuitry to use a single FCP isolation transformer on more than one band. Its winding ratio is 1:1. It's particular purpose is to not allow ANY direct path between the ANT/FCP and the coax side. One wire in the winding is connected to the FCP and antenna. The other wire is connected between the coax center conductor and coax shield. The 43' radiator has a number of problems on 160 which I am addressing in a separate post. It's feed impedance is but one of them. 73, Guy. On Sat, Jul 28, 2012 at 9:30 PM, Jim WA9YSD <[email protected]> wrote: > > Call Balun Designs you can purchase an 1:2 un to un balun. Here you have a > true way to feed a vertical. It works well for me. If you can measure your > input impedance at the feed point. It should be around 25 to 35 ohms. > You may have to re tune the vertical 43 feet is not exactly a quarter wave > resonate on any ham band. Resonate freq should be around 5.4mhz you may > have to add some aluminum wire. > The K2AV FPC balun is a 1:2 unbalanced to balanced balun. The same company > sells these as well. > Stay on course, fight a good fight, and keep the faith. Jim > K9TF/WA9YSD > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
