The important value is the resistance at the feed point of the radiator, independent of any matching devices used.
Adding a 4:1 or other transformer is simply adjusting the impedance the feed line sees, like any other matching network you might use. It has no effect on the feed point resistance of the antenna. A 1/4 wave long folded radiator has a feed point resistance of 4x the typical 1/4 wavelength radiator, quite independent of the ground system. Hence the efficiency is higher. 73, Ron AC7AC -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Roger D Johnson Sent: Tuesday, October 01, 2013 12:41 PM To: [email protected] Subject: Re: [Elecraft] Random wires This is NOT true! It merely raises the feedpoint impedance...just the same as adding a 4-1 transformer. 73, Roger On 10/1/2013 3:10 PM, Barry LaZar wrote: > > > As I read your post, I infer that at the moment you are wanting to > add 160 meters to your capability. An antenna that I have used and > liked is the Twin Lead Marconi. It's a simple, cheap, and effective > antenna. I first saw it written up by Bill Orr years ago. The premise > of the design is that a quarter wave antenna driven against ground may > not be the most efficient antenna due to low radiation resistance. > Therefore, raise the radiation resistance by using the theory of a > folded dipole. The folded element raises the radiation resistance by a > factor of 4 for 2 elements as the impedance changes as the square of > the number of elements. You will still need radials, but your ground losses will decrease. > > > 73, > Barry > K3NDM > > -- Remember the Liberty (AGTR-5) http://www.usslibertyveterans.org/ http://www.gtr5.com/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
