Sorry, I should have said "none" instead of "1:1". You don't appear to need it.
I also have a very compromised installation, but better now than a dipole. And, yes, a tidy installation does us a shocking amount of coax! Good luck, 73, Byron N6NUL On Mon, Sep 28, 2015 at 5:02 PM, Byron Servies <by...@n6nul.org> wrote: > 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. -- - 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
