The Helical Windom Antenna

A marriage of the windom and slinky antennas


Experimental home brew antenna

 A construction article by NC4TC


August 2011

The helical windom has been revived. My new condo has a bonus room over the garage, so I have hung it from the ceiling of the room.

More later

Before you read this article, please note that I have disassembled  this antenna. Although it was fun to build and it worked on at least a minimum level, I got discouraged with it. It was a pretty good receiving antenna but a lousy transmitting antenna. It was too low I think. NC4TC  4/8/2009

This antenna has been constructed to meet  the  homeowners covenant restrictions saying no visible outdoor antennas except for dish TV etc.

 

A panoramic view hand stitched so not as slick as Autostitch

just click on the area you would like to see enlarged 

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The following is a pictoral account of my experimental Helically wound windom antenna. A complete construction account will be forthcoming .


    

The components  of my helical windom

  1. RG8X mini low loss coax from The Wireman  coax #118
  2. 100 ft dual 18 gauge speaker wire from Big Lots  (cheap).  I ripped it apart for the antenna wire.
  3. 2 pieces 10 ft,  1.5 inch Diameter PVC conduit.
  4. Assorted cable ties.
  5. Coax hardware, PL239, PL259 etc.
  6. Balun Kit from the Wireman (see reference later).
  7. MFJ  204b  antenna bridge.
  8. Assorted tools not shown.
 


The pvc conduit was cut into 4 pieces  5',  5',  6',  4' 

I was anticipating locating it in my attic.

Actually it worked out very well for winding the antenna wire on it. 

I purchased a balun kit from The Wireman

 The Wireman Kit # 831

The instructions below  came with the kit.

The antenna measured approximately 450 ohms  so changing the instructions to read matching to 450 ohms,  with RG-8X coax (50 ohms) . Then 9-1 ratio becomes 450-50 


The Balun instructions were as shown above  but I redrew them to make an easier assembly for me

 

This was the first balun I have assembled

           Ready to be sealed

The balun was wrapped with linerless rubber tape which will seal it from moisture.

 

Secured with a cable tie and soldered to antenna ends which were later wrapped with vinyl tape.

The connection will also be waterproofed.

The white strips are white duct tape securing the ends of the wire.

 For some reason I could not find my gray tape.

 

The short end of the OFC (4 feet) and outdoor antenna workshop

 

1-1 air core   choke balun

My inspiration for this  balun was from   The ugly balun 

The long end of the OCF ( 16 ft)

The antenna wire was wrapped on separate pieces of conduit and joinned together and soldered.

The 16 ft. section is two 5 ft. pieces and a 6' piece.

The other section is  4 ft. joined to the feedline with the balun.

 

Looking North

 

 Another view

  

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