[Antennas] Antenna Design Help Please

2002年1月23日 09:32:42 -0800

Hi All,
I am still working on getting something that works well over the entire 160
meter band. I have a design in mind but, being blind, can't use EZNEC to
model it. So, would one of you gurus on here please model the following for
me if you have the time and let me know what you find. Please send private
replies to this address and cc to [email protected].
I have in mind to build a folded Marconi. Let's start with 130 feet of 450
ohm windowed ladder line. Short one end together and call this the
insulator end. Now, let's put this up as an inverted L with about 45 feet
of it vertical and the rest horizontal sloping to approximately 20 feet at
the end. At ground level, feed one side with the coax center conductor and
the other side with the shield. Attach at least one above ground, quarter
wave counterpoise to this shield connection. I would like to see what kind
of characteristics this antenna would exhibit. Next, using more classic
design, let's come back 7.5 feet from the insulator end (in other words,
123.5 feet out from the feed point) and short the line together thus leaving
the equivalent of a single wire for the remaining 7.5 physical feet. Does
this change the characteristics of the antenna greatly?
I would really appreciate any information anyone could give me as to how
this models. I have used similar antennas in the past made from 300 ohm
twin lead but not ladder line.
Thanks in advance for your help. 73
Kevin, K7RX
Kevin Nathan, Independent Living Coordinator
Dept. of Services for the Blind 
3411 S. Alaska
Seattle, Wa 98118
Voice: (206) 721-6450
Cell: (206) 604-4767
Toll Free: (800) 552-7103
Fax: (206) 721-6403
Email: [email protected]