Building Yagis – Part 4 (SteppIR DB36 Continued)


Element Truss Support

Element Truss Support

A combination of the weather and a big work project has slowed our progress on the first of two SteppIR DB36s this week. We did make some pretty good progress this weekend. The first step was to install all of the remaining hardware which attached to the boom in preparation for attaching the control wiring to the boom. This involved installing three element truss posts which will support the ends of the three large sweep elements. With this step done, I was able to tape the element control cables to their final position on the boom and loop the ends inside the control cable connector box for later wiring.

Connector Box and Element Control Cables

Connector Box and Element Control Cables

I also installed the 3″ mast clamp hardware to the mast plate.

Mast Clamps

Mast Clamps

The next step in the assembly of the DB36 was to prep all of the element poles. There are a total of 16 poles on this antenna – 4 each for the Reflector, Driven Element, and Director 2 and 2 for Director 1. Each of these poles had to be extended, cut to exact lengths and then sealed at the joints using the supplied heat shrink tubing pieces. We cut the poles using a power mitre box and a fine 60 tooth blade. This worked very well. After chamfering the small ends of the tubes so that they would not catch the moving elements, we carefully cleaned all of the dust from inside the poles with an air hose. We also decided to spray each pole with two coats of Krylon 1305 UV resistant Clear finish. This required each pole to be sanded with 400 grit paper, cleaned and then sprayed.

Element Housing Poles Prepped for Assembly

Element Housing Poles Prepped for Assembly

The picture below shows the new heat shrink tubing installed on the poles. This system is much better than the older combination of silicon and electrical tape. All of the pole prep and finished took us an entire day.

Element Pole Joints

Element Pole Joints

With the poles prepared for assembly, we assembled a pair of element sweeps housing for the Reflector and installed the vents in the end of the two Director 1 poles. We also glued together all of the pieces that make up the inner support tubes for each of the loop elements.

Element Sweep Assembly and Inner Support Tubes

Element Sweep Assembly and Inner Support Tubes

With all of the element housing assembly completed, the final step was to install the housing for the Reflector and Director 1 Elements on the antenna. We moved the antenna a more open area in our back yard behind the tower to make room for the installation of the element housing. As you can see from the picture, the antenna is starting to take shape.

SteppIR DB36 with 2 of 4 Elements Housings Installed

SteppIR DB36 with 2 of 4 Element Housings Installed

My work schedule will preclude any further work on the antenna for about a week. I hope that the next post will show the first completed DB36!

– Fred (AB1OC)

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