Club Meeting Presentations
Net Training for August 5, 2014: How to Send or Receive a Radiogram... How To Radiogram
For a look at the presentation on BALUNS, go to:
http://tinyurl.com/na7xgz8 (If the document fails to load, hit the BACK button on your browser and try again.)
The regular WTARS club meeting was held Thursday Jan 2nd at the EOC. Ben Barnett K4BEZ presented a NVIS antenna modeled after a military field antenna. You can view the presentation slides in PDF form by clicking Here. Here is a view of the parts less the fiberglass poles. The top of the antenna has a PVC end cap for weather protection.
Several hams present at the meeting expressed an interest in making this a club project. Thanks Ben.
The picture above shows all the parts necessary to make the portable antenna except for the coax, end insulators, and the bottom plastic "foot" that stabilizes the base of the fiberglass pole.
The black plastic box on the side is from Radio Shack. It's the small one about 3"x2"x1.5". The two antenna elements that have red connectors plug into 5-way binding posts. They are shorted inside the box which is connected to the center conductor of the RG-8X coax. The far side of the plastic box has the connectors for the shield side of the coax. The black box is attached to an aluminum "bud box" with a hole drilled into the end so it can slip over the male end of the fiberglass pole section. The Carabiner clips and the insulated rope are available from Harbor Freight and Wal-Mart. The wire and the end insulators can be obtained from various companies such as DX Engineering. The fiberglass poles can be obtained from Army Surplus in Trenton. They are $15.00 for a bag of 12 four-foot poles with metal ground stakes and the plastic feet.
The height of the antenna at the center is 20 feet (not 15 feet as in the diagrams). This allows a NVIS radiation pattern with almost maximum efficiency.