My today's experience was that my nice KX3/ATU which happily tuned my random wire when running from a power supply two weeks ago refused to load the same wire at the same location on all bands below 10 megs when running from the internal battery. However, I could convince it to tune the antenna while I was touching the case of the transceiver (I have been doing some simulations In order to gain some understanding why the german "Multiband-Fuchskreis" sold by a german Elecraft reseller seems to work in some situations and doesn't work for others and just used what I learned from my simulations)
Obviously the "counterpoise" was missing (or in my words the capacitance of the case to ground was not high enough). I could not test if plugging the headphones in and using them is sufficient to increase the capacitance sufficiently ;-) So, although not directly related to elevated radials, this former OT post has a relation to Elecraft equipment now ;-) BTW, is there any idea concerning the order of magnitude of the capacitance of a human body (6ft tall, normal weight) with respect to ground? Vy 73, Ralf, DL6OAP Am 19.05.2013 um 17:28 schrieb Walter Underwood <wun...@wunderwood.org>: > A vertical dipole can be balanced with the lower element shorter. It will > have more capacitance to ground, which makes it electrically longer. This is > like putting a capacitance hat on the end of an element. > > wunder > K6WRU > > On May 18, 2013, at 11:36 PM, Oliver Johns 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" <li...@subich.com> 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:Elecraft@mailman.qth.net >>>> >>>> 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:Elecraft@mailman.qth.net >>> >>> 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:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > -- > Walter Underwood > wun...@wunderwood.org > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
