220 Mhz 7 element home made beam

 

 This antenna  was design by a friend of mine Tom  WT2TT

 I built mine to his speciation, a great working beam..

The elements were just a little long than needed  So, I trimmed them to size I needed.

I first cut off the tops of the two folded dipoles that were hooked together, leaving the back one as a split dipole for the driven element. The forward one made as the first director. 

Reflector 26 inches

Driven element 24 1/2 inches

Director (all of them) 24 inches.  

Spacing from reflector to driven " 11 inches  equals .2 wavelength

All other spacing 9 3/4 inches between elements (metal to metal) equals .18 wavelength.

Supposed to be best gain and f/b. Will be sort of high Q, so bandwidth is less. But don't need that much bandwidth on that band. Most of the repeaters are around 223 to 224 MHz.

**the elements were riveted to the clamps and the clamps to the boom. I removed all the rivets and replaced with 1/4 20 or 10-32 machine screws/washers and nuts . In effect, put the antenna all back together again with the dimensions needed.

      I drilled new holes thru the boom to get the new spacing of all the elements. This luckily came out well that could fit from end to end a total of 7 elements. 

       I feed the driven direct with coax, yielding a 1.2 to 1 SWR. 

(foot note) If for some reason  a element is to short  a cheap curtain rod 3/8 inch will work ,

just a few dollars.

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220 Mhz 10 element home made beam

The 7 element work great , I found some more material

and made the antenna into a 10 element

 

 HERE IS THE 15 ELEMENT PLUS 6 ELEMENT BACK DOOR, THE BEAM IS REALLY TIGHT NOW ABOUT 15 DEG AND I LOOSE PERSON WHOM I'M TALKING TO....

HERE ARE SOME OF THE MOUNTING POINT I USED OR MADE WITH WHAT I HAD TO WORK WITH, PLUS HOW THE COAX IS CONNECTED.

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