To: | towertalk@contesting.com |
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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 _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk |
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