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Constructing a 2-meter 5/4 wave antenna, N1HFX details a design fully enclosed within 3/4-inch PVC tubing, addressing the significant velocity factor of PVC which necessitates a 19% reduction in physical length. The design incorporates a specific matching system using 300-ohm TV twin lead to counteract the highly inductive impedance component inherent in a 5/4 wave radiator. Key components include #18 stranded insulated wire for the radiating element, RG58/U coax, a PL259 connector, and a hardwood dowel for internal support, all carefully dimensioned for optimal performance within the PVC housing. The article provides precise cutting lengths for the twin lead and #18 wire, with the overall assembly measuring 77 3/4 inches, reflecting an approximate velocity factor of 0.81. Tuning instructions emphasize taking SWR readings with the antenna assembly inside the PVC, adjusting the #18 wire and twin lead in small increments to achieve a low SWR across the 2-meter band. The prototype antenna achieved SWR readings below 1.2:1 across the entire band, and N1HFX suggests an estimated 6 dB gain when properly mounted, offering a cost-effective alternative to commercial antennas.

A dual-bander for 80M and 40m. An Extended Double Zepp (EDZ) is a 5/4 wavelength center-fed dipole. This article will introduce the Half-Extended Double Zepp (HEDZ) which has characteristics that a lot of amateur radio operators should find quite interesting

Dual band vhf uhf dipole antenna by DL7JV

A three element wire yagi antenna for 7 MHz project plan with drawings and EZNEC model

A 4 element addition for 10m to an existing 4 element yagi (ZX antennas)