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Re: [TowerTalk] 4 Sq array Dx or Hi Z

To: towertalk@contesting.com
Subject: Re: [TowerTalk] 4 Sq array Dx or Hi Z
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 07 Sep 2012 22:52:27 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 9/6/2012 5:36 PM, Joe Subich, W4TV wrote:
flipping phase

Joe,

Please use the right word -- POLARITY when you mean turning the wires over to invert the signal. Phase is a continuously variable function and increases directly proportional to frequency. For example, a piece of transmission line that provides 180 degrees phase shift at one frequency provides a phase shift of 198 degrees at 1.1X that frequency, but reversing the POLARITY results turning the signal over at ALL frequencies. The difference between how these two methods of feeding antennas can be HUGE in terms of the maintaining performance over a desired bandwidth.

Engineers working in pro audio had to learn this 30 years ago when modern instrumentation made the difference glaringly obvious, and although it's critically important to hams, most don't even have a clue about the difference.

73, Jim K9YC
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