Can we possibly get back to topics that are relevant to Elecraft equipment. Find a different forum to talk antennas!
73,Tom (K7ZZ) On Sat, May 18, 2013 at 11:36 PM, Oliver Johns <[email protected]>wrote: > ELEVATED RADIALS: I think Joe hits it on the head here. A vertical with > elevated "radials" is essentially an OCF dipole. There is no particular > reason for the "radials" to be a quarter wavelength. They should be > whatever length lets you resonate the antenna with a feed impedance you can > live with. > > IMPT POINT: If you want your antenna actually to have a vertical > radiation pattern (low angle, omni-directional) then the elevated radials > must be symmetric. If there are two, they must be of exactly equal length > and point in exactly opposite directions. If there are four, they must be > equal and point in directions 90 degrees from one another. This symmetry > guarantees that the "radials" do not radiate. The do carry currents, they > do help resonate the antenna, but if they are symmetric radiation from them > cancels and they therefore do not radiate appreciably. > > 73, > > Oliver > W6ODJ > > > On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <[email protected]> wrote: > > > > > > Personally, I do wonder about the new fangled "no radials required" > > > antennas. But, I have an old R5 and it works well. > > > > The "no radials" antennas are basically a vertical OCF - the short > > decoupling radials are the short leg and the vertical is adjusted > > through the use of traps, stubs and/or loading to resonate on the > > desired band with the fixed length (typically 42") of the short > > "radials". > > > > 73, > > > > ... Joe, W4TV > > > > > > On 5/18/2013 9:25 AM, Bill wrote: > >> The cleanest installation is to put the radials in the ground - but, not > >> portable at all. The idea is a capacitance connection with the earth. I > >> have used welded steel cattle fence in the past - I build a mat that is > >> about 30 or 40 feet out from the base of the antenna. > >> > >> For raised radials - they must be resonate to function properly. Three > >> or four per band or related band. They have to be high enough that they > >> present no danger to anyone roaming around your antenna field. They can > >> be drooping or horizontal - both work well. > >> > >> Personally, I do wonder about the new fangled "no radials required" > >> antennas. But, I have an old R5 and it works well. Perhaps the way to go > >> is a new antenna that just gets bolted to a post and a feedline > >> attached. Sure makes life easier and from folks I talk to all the time - > >> they do work. Forget that they are a little expensive. You buy an > >> antenna to use for years. > >> > >> Read the eHam reviews and see what other users are saying before you buy > >> anything. Ask on the air. > >> > >> The best I ever had was a Butternut of some kind over a bunch of buried > >> fence. Might still be the way to go. But, if I was doing it now, I'd be > >> looking at a "no radials required" antenna. My reasoning is somewhat age > >> related. > >> > >> Be looking forward to the sage advice that will come from this post. It > >> is summer - so it is antenna time. > >> > >> Bill W2BLC > >> ______________________________________________________________ > >> 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 > > > > ______________________________________________________________ > 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
