I disagree. Barry has it right. The radiation resistance of the radiator is independent up the ground resistance. That's why a 1/2 end fed wire with it's very high resistance is highly efficient against a given ground system compared to a 1/4 wave long or less wire.
Note we are speaking of a folded full-length (i.e. 1/4 wave long) element. Folding short elements to make up for electrical length is something else entirely different. The Orr twin-lead antenna that I remember was 125 feet long, making it a full 1/4 wave on 160. 73, Ron AC7AC -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Vic K2VCO Sent: Tuesday, October 01, 2013 12:44 PM To: [email protected] Subject: Re: [Elecraft] Random wires Another way to look at it is that it multiplies the radiation resistance, but does the same for the ground resistance. So efficiency is unchanged. On 10/1/2013 12:40 PM, Roger D Johnson wrote: > 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 >> >> > -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ 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
