DK7ZB Dual-band antenna parts

thingiverse

These are the fastening elements and balun box with sealed cover for the DK7ZB dual-band (2 m and 70 cm) antenna https://www.qsl.net/dk7zb/Duoband/duoband_2-70_2-3.htm.This design has been made for the 20 x 20 mm boom.The tunable (+/- 1.5 mm) rod fastener is sometimes needed to optimize matching on 70 cm band. It can only be used for the Director 1 for 70 cm.In my case the Director 1 needed to be extended from 323 mm to 327 mm to achieve antenna resonance at 435 MHz.In the center of every antenna rod, there is a M2.5 threaded hole. A M2.5 x 5.0 DIN 7985 screw mounted there, helps keeping the antenna rods centered. If you have technical capabilities you can drill a shallower hole and use a shorter screw.There are two antenna box models provided. One is for horizontal mount and the other for vertical. The difference is in the position of the venting hole, that must always be on the ground side.The antenna box gasket is a 1.5 mm diameter rubber one.The heat staking inserts are M3 x 0.5 mm type, length 6 mm. Most common outer diameter is 4.6 mm.During the assembly, use some sealant at positions, where water could ingress into the balun box. This is not needed for the box cover.The distance between the mounting holes is 18.0 mm for both fixed and tunable rod fastener.Primoz S53KS