[TowerTalk] Pre-Installation Tuning of Cushcraft TEN-3 Yagi

Jason kb5urq at hotmail.com
Fri Jul 4 15:25:55 EDT 2008

I am in the process of checking SWR prior to installation of a TEN-3 Yagi (3 element Yagi for 10 meters).  The Cushcraft documentation states that I should temporarily mount the antenna with the boom vertical and reflector atleast one foot off the ground on a non-metallic support.

I have it 6 ft. off the ground mounted on a fiberglass ladder (non conductive).  

Using an MFJ-259 SWR Analyzer, I recorded the following data after adjusting the match on the driven element:
      Frequency     SWR 
      28.205 3 
      28.346 2.5 
      28.482 2 
      28.549 1.7 
      28.618 1.5 
      28.68 1.2 
      28.828 1 
      28.939 1.2 
      28.979 1.5 
      29.0298 1.7 
      29.076 2 
      29.158 2.5 
      29.227 3 

My goal is to tune this antenna for a resonant frequency of 28.3MHz and I have matched the dimensions provided by Cushcraft towards this aim.  I have tried extending the dimensions of the driven element by 2" but only moved the resonant frequency down to 28.647MHz.  

My question is whether  I should trust the Cushcraft documentation and put it up as they have described, assuming that the close proximity to the ground is disturbing my measurement.  

Thanks for any help / advice you can provide!

73 de KB5URQ


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