Home Brew Loading Coil for AD5X Vertical
Posted by Jim on January 14, 2007
This weekend, Dennis (N5DRB) and I made a loading coil for the second of our AD5X portable vertical antennas. The coil is also based on the design of Phil Salas, and you can see his article for making it at http://ad5x.com/images/Articles/CoilRevB.pdf .
We used a piece of 3 inch PVC pipe as the core, however we screwed 6 inch lengths of edge stip onto the pipe to hold them a little more securely while we wound.
We unwound about 6 feet of wire at a time and stretched it as straight as possible before winding it onto the form, trying to keep the tension even. This was definitely a two man job. Once the coil was wound, we masked the former with tape and filled the edge strip with 5 minute epoxy and let it set up overnight.
Next day, Dennis removed the coil from the form, which took a little effort cause we wound it on pretty tightly. He tapped gently on each of the four spacers to slide it off. He then fabricated the coil supports as described in the article using the 3/8″ fibreglass rod.
The final step is to solder the coil onto the brass rods and it’s ready to go…