Coax version






    Simple helicoidal

Pictures of the coaxial cable version

This will be the final result...

An example of how the element is mounted:
Fix (glue) the template to the vertical support, at the correct separation.
Drill with a small (2.5 to 3mm) drill, just inside the circle, from each side of the support (don't try to drill through.

Remove the inner part.
File (with a round file), and adjust the diameter to the horizontal supports.

Another example, here are the middle supports. Take note of the orientation of the holes drilled for the coax support.
Drill the horizontal support at each end (90 degrees difference), to pass the coax cable in the right direction.

Similarly, prepare the holes for the BNC connector. Drill the mounting holes with the right diameter for selftapping screws.
The drill the center hole for the connector.

File, to obtain a flat surface for the connector.
Here the BNC connector, being prepared before mounting.

This is the second support being prepared for connection to the outer loop. These holes should be on one side only!

The cable being prepared for connection to the outer loop.
Remove the outer sleeve for about 4 cm.

Without cutting the braid, remove inner polyethylene isolation.
Twist the braid, joining it with the inner conductor. Then bend them, near the end of the sleeve, at 90 degrees, to help passing them through the holes.

The lower of the top two tubes installed, with the twisted coax ends protruding through the two holes.
This is the correct way to connect them with the outer loop.

Connection drawing: Upper and lower connections. Both are top views, i.e. looking down on the connection
After more than five years of faithful service, back home. Here's a picture though the connection hole at the connecter. Compare with the bottom part of the drawing

The five years in the sun takes its toll on cheap PVC tubing. The inferior quality I'd used for the center supports shows clear pitting.
Top and bottom supports are dulled but not that harmed by UV. Still, it doesn't seem like a bad idea to paint the antenna

The BNC connector (an old silver-plated one) looked fine. So did the vertical pipe (PVC drainage).

(c) John Coppens ON6JC/LW3HAZ mail