Building Yagis – Part 7 (Second SteppIR DB36 Completed)


Completed Second SteppIR DB36

Completed Second SteppIR DB36

We completed the assembly of our second SteppIR DB36 Antenna today. This is the last of the Yagi antennas for our new antenna system and tower. It will be installed on a KoXG Rotating Ring at 60 ft on our tower. The second DB36 will be able to be used as part of a 4 over 4 array, or it can be connected to a second feedline via the Custom Breakout System that we built to allow Anita and I to operate simultaneously. Our second SteppIR DB36 is identical to the first one at 101 ft except that it does not have the 80m dipole option installed. We elected not to install the 80m dipole on the lower DB36 as 60 ft is not really high enough for a dipole on 80m to be effective for DX work.

We covered the assembly of our first SteppIR DB36 in detail in a series of posts so we will only provide a summary of the assembly process for the second one. You can access the posts on the first DB36 via the following links:

There are some important differences between the second DB36 and the first one and I will cover those here. The first difference relates to the installation of this antenna on the K0XG Rotating Ring. The ring uses a boom clamp instead of a standard mast clamp system.

K0XG Ring Clamp

K0XG Ring Clamp

This required some U-bolts to attach the ring clamp to the boom of our second DB36 and to attach the boom truss pipe for the second DB36 to the clamp. Our local Hardware Store had clamps that we could use and after some modifications, including extending the threads on the clamps, glass beading, and a good coat Cold Galvanizing Paint, the K0XG Ring Clamp was secured to the boom of the second DB36. We were careful to locate the clamp in a position that would not interfere with the installation of the 6m passive which was to come later.

Ring Clamp on Boom

Ring Clamp on Boom

The only other difference in the second DB36 was the absence of the 80m dipole option. This simplified the connector box wiring on the second antenna a bit.

Control Cable Junction Box

Control Cable Junction Box

The second DB36 will be part of a 4 over 4 array so its important that the feedlines and related elements in the transmission path between our DX Engineering Broadband Phasing System and both antennas be identical. The upper DB36 has the 80m dipole option installed which inserts a 6 ft length of RG-213 coax and a switching relay into the feedline path of that antenna. To ensure identical performance of for the feedline system of the lower antenna, we installed the switching relay and the RG-213 coax on the lower antenna as well. Since we do not have the 80m dipole option installed on the lower antenna, the switch does not need to be connected to the control cable for the antenna. The addition of these components did affect the SWR readings on the ground and brought the SWR measurements closer to the first antenna indicating that the expense of the additional components to make the feedline systems a match was justified.

80m Dipole Switch and Coax

80m Dipole Switch and Coax

We tested the second DB36 on the ground to confirm that all of the elements were operating properly and that the SWR performance was consistent with the first antenna and repeatable. Everything checked out fine.

Antenna Test On The Ground

Antenna Test On The Ground

The last step was to tape up the rubber boots which hold the element housings in place. These boots are prone to UV damage and subsequent failure. The tape protects the boots from damage from the sun and extends their life.

Taped Element Boots

Taped Element Boots

Our second SteppIR Db36 is now complete and will go on our tower tomorrow. As I mentioned in a previous post, the assembly of one of these antennas is a fairly big project. There are approximately 1,136 parts in a fully optioned SteppIR DB36 antenna! We took quite a bit of additional time to carefully assemble our two DB36’s and to protect them from the weather and sun as much as possible to extend their life. Some of the “added steps” included:

  • Wiping all metal parts with a solvent to remove any oil or dirt followed by a coat of WD-40
  • Treating all plastic and rubber parts with a coat of ArmorAll to improve their UV resistance
  • Coating all Fiberglass Parts and Poles with two coats of Clear UV Resistant Paint
  • Taping all of the Rubber Element Connecting Boots to Protect them from UV related deterioration
  • Extra time spent on carefully leveling the elements and the boom truss to ensure that the antenna was perfectly straight
  • A through set of resistance and operational checks of the antenna on the ground before installation on the tower
  • A second, final check of all hardware for proper tightness

I am sure that others have assembled one of these antennas in considerably less time than we did. I would estimate that each one required 50 – 60 total hours to complete (about 1 full-time week). The second one required less time than the first as a result of the experience gained with the first antenna as well as the lack of the 80m dipole.

The next step will be to put the second DB36 on the tower and test the stack. This will be the subject of a future post.

– Fred (AB1OC)

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