[amsat-bb] Re: Helix matching
jfitzgerald at alum.wpi.edu
Fri Sep 27 16:05:49 PDT 2013
On 9/27/2013 8:57 AM, Robert Bruninga wrote:
> Why don’t 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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