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Trap Dipoles Ageeeeeeen….Part 3

[edited for links and notes, 2023/07/15] The original trap dipoles were constructed using coils and caps. Using Rg-58 for the coax style trap dipoles was rejected because of the weight and size of rg-58 coax traps. Using RG-58 defeated the primary goal of making the antenna as light weight as possible.

Somewhere I picked up the notion of using rg-174 or rg-316 type mini coax to make the traps. It looks like the voltage ratings on the rg-174 is higher(1100v rms), so that was chosen for the first experiments. If luck holds out, the tiny coax will be sufficient for use on the dipole traps for a full 100w CW. Using the smaller lighter mini coax will allow for lightweight construction from easily available materials that can be easily supported using telescoping fiberglass masts like those available from Spiderbeam, MFJ, or Jackite. i.e., perfect for portable, field day, rover QSO parties, or POTA/SOTA.

The trap calculator program hosted by KC1KCC gave me some starting numbers to work with, and actual trap measurements came out quite close to the calculated values. [alternate calculator at K7MEM]  The traps are built with the coax coils wound reasonably tight to the form, and the coils were taped down with electrical tape prior to taking measurements. These are all wound on small sections of the same sort of plumbing drain tailpieces that are 1.5″ od (38mm od). (e.g., in the US available from Lowes or any hardware store selling plumbing supplies.) The table below […]

Continue reading Trap Dipoles Ageeeeeeen….Part 3