Dan's original post concerned the effectiveness and practicality of various EFHW configurations in a man pack environment. Since he had already decided that his radiating element will be 1/2 wavelength long, the primary concern is power transfer efficiency vs. practicality of the solution in a weight and space constrained man pack environment.
For the entire history of radio, RF ammeters have been used to evaluate the efficiency of alternative matching systems and their associated radial/counterpoise systems. An RF ammeter could be placed in Dan's EFHW antenna -- ideally in the center -- to compare the relative performance of practical man pack EFHW implementations. 73 Frank W3LPL ----- Original Message ----- From: "Don Wilhelm" <[email protected]> To: "Wes Stewart" <[email protected]>, [email protected] Sent: Sunday, February 12, 2017 6:29:07 PM Subject: Re: [Elecraft] EFHW Wes, I do not doubt what you are saying about 1/2 wave verticals, but most EFHW antennas are mounted as a sloper or a horizontal antenna. For portable operation, the main concern is for the ability to feed the antenna, and not about maximizing the far field strength. 73, Don W3FPR On 2/12/2017 12:34 PM, Wes Stewart wrote: > Alas, if only this was true. > > Google "radial system design and efficiency in hf verticals" and you > should get a cached version of Rudy Severns' paper of the same name. In > it he states: > > "Alternately we can graph efficiency in terms of Ga as shown in figures > 3 and 4. Unfortunately this also shows how inefficient verticals are > even over very good ground. Very depressing! For example, with very good > soil (0.02/30) and 128 1/2-wave radials, the efficiency of a 1/4-wave > vertical is still only -2.76 dB (53%)!" ______________________________________________________________ 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 Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
