[amsat-bb] Re: Helix matching
Edward R Cole
kl7uw at acsalaska.net
Fri Sep 27 23:27:58 PDT 2013
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.
73, Ed - KL7UW
Joe: note the KLM-11 el yagi made from a KLM-22C I got from you years ago:
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..
>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.
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73, Ed - KL7UW
dubususa at gmail.com
"Kits made by KL7UW"
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