[AMPS] Parallel coaxial feedline For 1/2 Characteristic Impedance

Phil (VA3UX) phil@vaxxine.com
Sun, 17 Dec 2000 11:52:03 -0500


Well I was close.  The article by VE2CV ("Transforming the Balun") is on
page 30 of June 1991 QST. It describes using a pair of 93 ohm cables in
parallel with ferrite beads to make a balun.  However there are references
in the Notes section of this article to other articles where balanced
feeders were constructed from pairs of coax.  I also seem to remember that
Belrose did a follow-up article on running parallel coax lines. 

Phil

>Date: Sun, 17 Dec 2000 00:16:00 -0500
>
>You may not be the first Billy.  This idea rings a bell.  I believe VE2CV
(Jack Belrose) wrote an article about this very thing in QST just a few
years ago.  I'll have to track down the article to be sure we're talking
about the same thing.
>
>Phil
>
>
>At 05:03 AM 12/17/2000 -0000, you wrote:
>>
>>Greetings Group,
>>
>>
>>The Idea was to use two 72-Ohm Belden cables in parallel to obtain 36-Ohms 
>>to match a 32-Ohm 1/4 wave ground-plane antenna.  In doing this, the I 
>>squared R losses would also be 1/2 unless there is something that I am not 
>>seeing. Since the tests show that it works,  if I qualified the tests 
>>properly, I would have no doubts except that I have been a Ham and a RF 
>>engineer for almost 40 years and have never heard of  running two cables in 
>>parallel.






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