> > But most hams have too little acreage for anything even close to 1/4 WL > (521-foot).
The height restriction is 60 m (~197 ft). 73 de AI6KG On Wed, Sep 20, 2017 at 9:19 AM, Edward R Cole <kl...@acsalaska.net> wrote: > N6LF is also WD2XSH/20 whose 630m CW signal I copied up here. Rudy moved > a couple years ago to new property and has new antenna farm. > I believe his study of elevated grounds was published in QEX and later in > QST. > > Virtually all transmitting antenna for 630m will be "short" verticals so > his findings are useful if you consider getting on 630m. EZNEC-5 indicated > my radiation resistance would only be 0.83 ohms with a 43-foot high > top-loaded vertical. Actual measurement showed 18 ohms so efficiency is > 0.83/18 = 0.046. My ground plane is woefully too small: four 70-foot by > 2-foot wide runs of chicken wire on ground. But most hams have too little > acreage for anything even close to 1/4 WL (521-foot). > > My antenna consists of three parallel vertical wires spaced 1-foot apart > and shorted by a 1/2 inch copper tube at both top and bottom; horizontal > leg is two parallel wires spaced 2-foot and 122-foot long (like-wise with > copper tube shorting bars). The parallel wires lower Q a bit to widen the > SWR bandwidth which is about 5-KHz. Extra horizontal wire increases > top-hat capacitance which makes vertical look longer. > > I will make a new webpage to show what I am using on 630m (old webpage was > hacked several years ago and I never resurrected the 600m page). > > I may still get my inverted-L repaired and rehung with aid of my prof. > tower person, though winter wx is not far off up here (freezing temps > expected within a week). > > 73, Ed - KL7UW > I will probably play with running WSPR and the new FT8 digital modes on > 630m. > > Date: Tue, 19 Sep 2017 11:09:10 -0700 > From: Jim Brown <j...@audiosystemsgroup.com> > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] 630M Antenna > Message-ID: > <42665049-96ff-0df1-7138-242ff9277...@audiosystemsgroup.com> > Content-Type: text/plain; charset=utf-8; format=flowed > > N6LF's website should be required reading for anyone intending to > operate these new bands. He's done extensive work on antenna systems for > these bands. > > 73, Jim K9YC > > > 73, Ed - KL7UW > http://www.kl7uw.com > Dubus-NA Business mail: > dubus...@gmail.com > ______________________________________________________________ > 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 > Message delivered to c...@murgatroid.com > ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
