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Re: [TowerTalk] real world formula for the length of a quarter wave tran

To: towertalk@contesting.com
Subject: Re: [TowerTalk] real world formula for the length of a quarter wave transmission line
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 13 Feb 2013 21:16:43 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
And don't forget that Vf varies a bit with frequency (it's slightly lower at lower frquencies). The difference is small, but enough that you want to carefully tune the stub at the frequency that you want it to reject. The difference is greatest on the lower ham bands, enough that you won't get as much suppression as you expect because it's a bit off frequency, and not big enough to matter above 20M.

More about this in my Coax and Stubs tutorial, previously cited.

73, Jim K9YC

On 2/13/2013 9:07 PM, Jim Lux wrote:

So, for a top of 75meters 1/4 wave, it would be 246*VF/4 or 61.5*VF

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