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Building Antennas from Everyday Materials. by Marc C. Tarplee Ph.D., NCE N4UFP. The Problem. We’ve all seen commercially built antennas or construction plans for antennas in magazines like QST or CQ We’ve also seen wire models of antennas that are used by simulation software.
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Building Antennas from Everyday Materials by Marc C. Tarplee Ph.D., NCE N4UFP
The Problem • We’ve all seen commercially built antennas or construction plans for antennas in magazines like QST or CQ • We’ve also seen wire models of antennas that are used by simulation software. • In every case we usually ask ourselves the following question: • How to I build the #@$% thing?? • Many projects call for aluminum tubing, stainless steel hardware, fiberglass insulators, gamma matches, etc. and require the use of tools such as a drill press or lathe for construction.
The Solution • See what materials are available locally. • Home improvement stores • The local hardware store • Auto parts stores • Use designs that can be constructed from those materials. • Loops with wire elements • Wire yagi designs (Moxon, Hex-Beam, etc.)
Conductors/Radiators • #14 or #12 THHN stranded copper wire • Inexpensive ( 7 – 12 cents/ft) • Insulation adds strength and protection from the elements • Aluminum welding rods • Available in various lengths and diameters. • Easily fabricated • #10 bare solid copper wire • Stiff enough to be used for self supporting elements • Flexible and can be soldered/brazed. • Aluminum angle/channel • Can be bolted together to make longer elements • Radiators do not have to have a circular cross section!! • Type L copper water tubing • Can be bent and soldered • Relatively heavy – may not suitable for large radiators.
Insulators • Acrylic sheet • Can be cut by scoring and drilled • Good dielectric strength • PET (polyethylene terephthalate). • Used to make soda bottles • Good dielectric strength • Can be cut with scissors • Non-biodegradeable • Wood • Available in many sizes and shapes • Easily drilled and cut • Should be painted to prevent water absorption • PVC pipe • Easily worked with hand tools • Good dielectric strength • Non-biodegradeable
Booms and Spreaders • Screen Molding (0.375x0.75 inch) • Can be used for lengths up to ~ 8 feet • Should be painted • Bamboo fishing poles • Can be used for lengths up to ~15 feet • Should be varnished to prevent deterioration • Fiberglass fishing pole blanks • Lighter and stiffer than bamboo • Non biodegradeable • PVC pipe • Many varieties of pipe and fittings available • Combination of high density and flexibility make it unsuitable for long booms/spreaders.
Example: 6m Moxon Rectangle • Wire used for elements • Screen molding used for spreaders • Insulators were made from a 2 liter Coke bottle. • Everything fastened with standard #6-32 hardware • Weight < 5 lbs
Example: 8 element 222 MHz Yagi • Boom – screen molding • Parasitic elements – 1/8 inch diameter aluminum welding rod • Driven element - #10 bare solid copper wire.