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Re: [TowerTalk] coax 'sweet lenght'

To: <>, <>
Subject: Re: [TowerTalk] coax 'sweet lenght'
From: "Tom Rauch" <>
Reply-to: Tom Rauch <>
Date: Sun, 10 Oct 2004 13:07:10 -0400
List-post: <>
 > > So as Dave says, it is a myth that a line feeding a
> > antenna  has a specific "sweet length". If the system is
> > behaving properly, SWR is constant.
> Exactly right!  And if SWR>1.0 then the impedance at the
> end of the line changes with differing line lengths, so a
change in
> line length can sometimes make it easier to match for your
> transmitter (i.e. the length might seem to be the "sweet
> hence the birth of the myth.)  That length is likely to be
> for different bands, so the term "single antenna" should
probably be
> "monoband antenna" for any given line length to be

What I intended to exclude were cases where multiple
elements or antennas are fed at the same time, such as a
stacked, collinear, or phased array.

But you brought up a very good point, many radios work
better into an impedance higher or lower than exactly 50
ohms. Even if SWR does not change along the line or at the
radio, the radio might be happier with a mismatch in some
specific phase angle area.

73 Tom


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