[Elecraft] 630M Antenna

[Edward R Cole]

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 <jim at audiosystemsgroup.com>
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] 630M Antenna
Message-ID:
         <42665049-96ff-0df1-7138-242ff92775d9 at 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:
   dubususa at gmail.com