[VHFcontesting] tuning a 6M plumbers delight dipole fed with a current balun

[Mike & Becca Krzystyniak]

Greetings,

 

     I was digging in my tubing bone pile to make a 6M Dipole.

     I came up with enough HyGain hardware scraps for 1/2" elements 

     and insulated element to boom bracket for same.  I had a Balun Designs

     balun laying around rated to 54 MHz to feed the dipole.

 

     The elements were cut to quarter lengths (234/F) plus a couple inches
for trim/tuning.

     Using my AA-55 hand held analyzer I was surprised to see the antenna
resonant at 45 MHz.

 

      I'm guessing the "antenna element" resonance has to include the straps
back to this balun?

      Also there is ~2-3" of tube burried inside the plastic insulator
sandwiched in element to boom 

      bracket which probably looks more like a shunt cap to ground.

      There is about ~4" of strap from the exposed element that connects the
Balun box.

 

     Wondering if anyone has tried to model and/or build an assembly like
this?   

     Thinking about it some it looks more like a Delta match.

 

     I did one 2" trim and it shifted the resonance to 47 MHz.

     Another 3" should hit 50 Mhz but that means the actual radiators are
some 4-5% shorter than 234/f predicts.  

 

    Has anyone else experienced this extra shortening of a dipole or yagi
driver whe using an boxed 1: 1 current balun? 

 

Thanks

 

Mike K9MK