On Sat, Feb 11, 2017 at 11:19 PM, Kevin - K4VD <[email protected]> wrote:
> ...The end fed is only 10% efficient (did I get that right)... ========== No, that's not right. The radiation pattern and gain of an end-fed halfwave are little different from a center-fed dipole. The efficiency of an antenna is not affected by feedpoint location. The end-fed antenna may be harder to match than a center-fed, but that's a different question. If you have a proper matching arrangement between the antenna's high impedance and your feedline, you'll get results that are essentially identical to a standard doublet. As I mentioned in an earlier post, two minutes with EZNEC will clarify this. "Efficiency" refers to the quotient of the antenna's radiation resistance, divided by ohmic losses. If you have a short piece of wire, its radiation resistance will be low, but for a half-wave wire it's 73 ohms, no matter where it's fed. As a side-note, I worked over 300 countries with a 100-foot wire strung out my bedroom window (16 feet above the driveway) and running to a tree at the end of the yard, 40 feet high at the far end. There's a picture of it on my qrz.com page. Tony KT0NY ______________________________________________________________ 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]
