On Mon, Sep 28, 2015 at 4:37 PM, Douglas Hagerman <douglas.hager...@me.com> wrote:
> > I have a space-limited dipole for 20 meters with drooping ends. The KAT-1 > tuner > will tune it. What I want to know is whether to use a 4:1 or 1:1 balun, or no > balun, > at the antenna. > Are you feeding the antenna with coax or ladder line? Even a low dipole will have a feed point impedance of roughly 75 ohm, so 1:1 would be fine with coax. You may want to consider a current choke at the feed point, but that's up to you. With 450 or 300 ohm ladder line, a 4:1 would be more appropriate to match the feedline to the expected impedance of the K1 input. > If the tuner reports 24 “x10” pF, is that 240 pF or 2.4 pF? A straight reading > suggests that it’s 2.4 pF, but I don’t see how the tuner circuit can provide > so > little capacitance. But C4 (82 pF) plus C5 (150 pF) gives 232 pF which could > 240 pF if you include some parasitic capacitance, maybe? Xc = 1/(2 * pi * 14 x 10^6 * 240 x 10^-12) ~~ 47. So, the tuner thinks it is seeing roughly 50 + j47 and needs -47 of capacitance to balance it out, right? I'd go with the 1:1. 73, Byron N6NUL -- - Northern California Contest Club - CU in the Cal QSO Party 3-4 Oct 2015 - www.cqp.org ______________________________________________________________ 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
