[Elecraft] Random wires

[Barry LaZar]

Bill,
     I have used/built/designed many antennas over the years. I have had 
a number of favorite antennas over along ham career. My only concerns 
have been line loss due to SWR and launch angle. There have been a few 
minor concerns like can I really put that thing up or not.

     As I read your post, I infer that at the moment you are wanting to 
add 160 meters to your capability. An antenna that I have used and liked 
is the Twin Lead Marconi. It's a simple, cheap, and effective antenna. I 
first saw it written up by Bill Orr years ago. The premise of the design 
is that a quarter wave antenna driven against ground may not be the most 
efficient antenna due to low radiation resistance. Therefore, raise the 
radiation resistance by using the theory of a folded dipole. The folded 
element raises the radiation resistance by a factor of 4 for 2 elements 
as the impedance changes as the square of the number of elements. You 
will still need radials, but your ground losses will decrease.

     Another antenna that I have used successfully is the center fed 80 
meter dipole fed with open wire feeder. With an antenna tuner it's an 
all band antenna and losses are low because you are using open wire 
transmission line. A 4:1 balun located near the point where you egress 
your house allows you to transition to low loss coax, like LMR-400. I 
use a variant of this during Field Day where one of our runs is 370+ 
feet long. This works fine with QRP; look for NA3DX in the rankings when 
the ARRL publishes the FD results.

73,
Barry
K3NDM


On 10/1/2013 2:35 PM, bill.va3ol at gmail.com wrote:
> My antennas for the past few years have been Alpha Delta Dipoles (an 80/40
> and a 40-10) plus an 88 foot CFZ. When I began looking for a 160 meter
> antenna I came across the Balun Design website which had a 9:1 unun plus an
> article on using it with a single wire for all band performance. It sounded
> to good to be true and you know the old saying ...... it probably is.
> Remember that I have a 125 foot run of coax to a remote antenna switch up
> the hill, in my little forest so line losses due to SWR are a major
> concern.
>
>
>   Well, I ordered their 9:1 unun and hung a 124 foot inverted L set up at 25
> feet. My experience tells me that it is worth the trouble to get it up
> higher once the leaves are gone. The original radial system was 8 – 10 foot
> radials, 2 - 15 foot radials and 1 - 30 foot radial.
>
>
>   Here are my initial findings:
>
>
>   160 meters: less than 3:1 across the band
>
> 80 meters: less than 4:1 across the band
>
> 40 meters: less than 3.5:1 across the band
>
> 30 meters: less than 1.5:1
>
> 20 meters: between 2.1 and 1.1
>
> 17 meters: between 2.5 and 2.1
>
> 15 meters: between 1.7 and 1.5
>
> 12 meters: 1.7 across the band
>
> 10 meters: less than 1.7 across the band
>
> The above measurements were made with a Rigexpert AA-54.
>
>
>   After tweeking the radials, spreading them out more and adding a few more
> longer radials I used K3-EZ software to sweep each band and got very
> similar results. My goal was to get access to 160 which I achieved along
> with access to all of the WARC bands as a bonus. I should mention that I am
> using the 5kw version to allow for the added stress of a higher than
> desired SWR and an amplifier on occasion.
>
>
>   The BalunDesigns.com website has the article linked from this page:
> http://www.balundesigns.com/servlet/the-106/9-cln-1-9-dsh-1-unun/Detail
>
>
>   I have no interest in the company, etc. Etc.
>
>
>   Bill, VA3OL
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