Making these matching sections is not as critical
as many made them out. Here is a 1420-MHz dish
feed helix I built years ago. I used the same
technique for the 2.4 GHz helix feed I used for AO-40.
http://www.kl7uw.com/1420helix.jpg
73, Ed - KL7UW
Joe: note the KLM-11 el yagi made from a KLM-22C I got from you years ago:
http://www.kl7uw.com/HF.htm
scroll down to set of three photos. The KLM-11
is mounted just below the tribander
At 03:05 PM 9/27/2013, Joe Fitzgerald wrote:
On 9/27/2013 8:57 AM, Robert Bruninga wrote:
Why dont we see simple ¼ wave 75 ohm lines used as a first step in
matching a 140 Ohm Helix to 50 ohms?
In my limited experience, it's easier to diddle
around with a strip of brass or copper at the feed end of the Helix..
For example:
http://www.amsat.org/amsat/articles/g3ruh/117.html
I remember building a 1/4 wave coaxial matching
section out of a piece of copper pipe with brass
rod down the center. I think it was from a
design in the ARRL antenna book as published in
the late '70's. It was a pain to build since I
had to sand down the brass rod to get it to the
right diameter, and I was never really sure how
well it worked, since I did not have any antenna instrumentation at the time.
-Joe KM1P
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73, Ed - KL7UW
http://www.kl7uw.com
dubus...@gmail.com
"Kits made by KL7UW"
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