Your Guessing ! Did you Model it ??? Then you will know…….. Ray WA6VAB K3
Windows 0 From: Bob McGraw Sent: Saturday, October 30, 2021 6:17 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] center fed dipole I don't understand the use of the 4:1 balun. On 80M the feed Z of that antenna is more likely 25 to 50 ohms. The 4:1 balun would present a impedance to the RG-213 of 6.5 to 12.5 ohms. You would be much better with a 1:1 balun configuration. Remember one is not matching the feed line impedance but is matching the antenna impedance. The ideal use of a 4:1 balun is with a folded dipole antenna which presents a 200 to 300 ohm impedance. Now the feed line Z is much closer matched and the 4:1 balun gets the Z to the coax in the 50 to 75 ohm range. Much more efficient. This of course is a single band antenna. See https://www.dj0ip.de/balun-stuff/ for good, accurate, and reliable information on baluns and their usage. Most hams have it wrong as well as most manufactures of antenna tuners who include a 4:1 balun. 73 Bob, K4TAX On 10/30/2021 5:07 PM, elecraft-requ...@mailman.qth.net wrote: > Message: 11 > Date: Fri, 29 Oct 2021 18:25:44 -0700 (PDT) > From: MIKE ZANE<n...@comcast.net> > To:"Elecraft@mailman.qth.net" <Elecraft@mailman.qth.net> > Subject: [Elecraft] center fed dipole > Message-ID:<1705203692.528740.1635557144...@connect.xfinity.com> > Content-Type: text/plain; charset=UTF-8 > > I have no problem with a 130 ft dipole fed with 25 feet of 450 ohm ladder > (window) line to a 4:1 4K balun with 15 feet of RG-213 to my MFJ 989C tuner. > I have run from 5w to 1 KW with it....no problems at all. n6zw ______________________________________________________________ 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 wa6...@gmail.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 Message delivered to arch...@mail-archive.com
