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[TowerTalk] 50:75 ohm transformation

To: <towertalk@contesting.com>
Subject: [TowerTalk] 50:75 ohm transformation
From: john@jrh.com (John Hunley)
Date: Wed, 10 Feb 1999 14:06:11 -0500
Which begs the question (at least in my limited little mind ;-)):

Given the availability of such vast quantities of 75-ohm cable, often quite
inexpensive or free, why don't ham equipment and antenna manufacturers just go
with the flow and design for 75 ohm impedances, or at least make it optional?
What's magic about 50 ohms, anyway?

John Hunley, N9JH

DavidC wrote:

> Local contester KM1H runs 75ohm CATV to all of his HF, VHF and UHF antennas
>
> without UNUNs and says the impedence bump over several hundred foot runs
> are
> unnoticable, especially since the loss in such cable is so low.
>
> He also says that he has discovered that many antennas are closer to
> 60 ohms than 50, so 50 ohm cable also sometimes introduces a mismatch.
> He is now building his own long-boom beams for 6 meters so I suppose he
> can optimize those for 75 ohms and have the best of both worlds!


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