SteppIR 4-Element Yagi

SteppIR 4-Element Yagi  (July 30, 2007) 

The original W8UM tower, the heart of our amateur radio station and a long-time dream for all club members, was raised on July 30, 2007. The station’s main antenna support is a guyed 40 ft Rohn 55G steel tower mounted on top of the EECS Building on Michigan’s North Campus. The tower supports a wide variety of transmission and receive antennas covering 3.5 MHz to 1.2 GHz.  The guy lines are Phillystran dielectric cable to eliminate guy line-antenna interaction. 

Properly designing and erecting a roof-top tower was no simple feat. The tower, base, and guy support design were done by the Lonberg Design Group. Tower construction was done by Matt KC1XX and Andrew of XX Towers. In under 8 hours, the tower, guys, rotator, mast, and all antennas, and related equipment were installed and W8UM was on the air. All the club members on hand (and several others around campus on the ground) commented on the graceful and efficient construction process. 

The tower’s success was in large part due to long-term planning, financial support from U-M and our alumni and friends, and some serious, hard work by the club members. Richard KD8APA managed the entire project, overseeing the design, parts procurement, contracting, and budget since January 2006. In the final stretch, Bill AA8RW and Helen KG8TQ assembled much of the antenna hardware including the large SteppIR HF Yagi. Steve K8QKY, Dennis KT8X, Dave WS8P, Pat WA4DSR, and Mark WD8DPA were also a great help during the long tower raising weekend. Most of all, we are grateful for the generous financial support from the Club’s alumni and friends and the U-M College of Engineering and EECS Department. Thank you for sharing our vision of a world class amateur radio station at the University of Michigan.

SteppIR 4-Element Yagi (September 7, 2021) 

On September 7, 2021, severe thunderstorms passed through N.E. Ann Arbor. This was followed by a second severe thunderstorm on October 21, 2021.  In the days following, individuals from the Amateur Radio Club reported the inability to use the SteppIR antenna. This antenna, located on the EECS roof, is the main antenna for the amateur radio club. Testing of the antenna disclosed an extremely high and erratic signal wave ratio.  This led members to investigate the likelihood of a broken coax connection or possible lightning damage to the SteppIR antenna.

On October 30, 2021, a tower climb, to inspect the coax connection at the Poly-Phasing (lightning protection) connection on the tower, was completed. Arcing was noted on the center conductor pin and within the coax cable. A TDR, from the lightning protection connection to the Driven Element on the SteppIR antenna, was performed where a second “open circuit” was noted.

1. 1478’ from the Tower
2. 2270’ from the Tower
3. 2746’ from the Tower
4. 2904’ from the Tower
5. 3062’ from the Tower
6. 3221’ from the Tower
7. 3485’ from the Tower