Craig's Photo Album - Multi-Dipole Antenna

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Home > Ham Radio > 2005 > Multi-Dipole Antenna

Multi-Dipole Antenna

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From the rooftop – 371 viewsThe antenna is mounted just 8-10 feet above my roof line. I have no usable trees to which to connect the ends of a dipole, so my only option are simple masts on the peaks of each end of the roof, which are coincidentally about 70 feet apart.

20M Support – 189 viewsA piece of 1/2" PVC about 10" long holds the end of the 20M dipole suspended from the 40M dipole above it.

10M Support – 186 viewsA piece of 1/2" PVC about 20" long holds the end of the 10M dipole suspended from the 40M dipole (top). The 20M dipole passes alongside the support and is connected to it via a tie wrap.

Center Insulator – 295 viewsAll three dipoles are connected in parallel to the RG8 feedline. The center insulator is suspended on a piece of PVC. About 21 feet of RG8 is coiled at the feedpoint as a balun to match the balanced antenna to the unbalanced feedline. This is supposed to keep the coax from radiating.

The Whole Antenna from the Back Yard – 343 viewsThe antenna was a little difficult to tune because each element is affected by the length of the other elements. As I adjusted the 20M antenna, the 40M resonant frequency would move a little bit. The 10M resonant frequency moved more, and in the opposite direction. In the end I have 2:1 or better SWR across the CW portion of each band and in some cases well into the phone band. I use the Elecraft KAT100 tuner to get 1:1 on all CW and phone segments of 80M - 10M.

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