Arcing appears to have caused a tower fire on the FM master antenna system at the foothills of the Tiger Mountain tower site earlier this month. The site is about 20 miles east of Seattle.
Electronics Research Inc. President Tom Silliman told Radio World, either storm damage or vibration caused a bolt to break inside a fiberglass insulator. That led to arcing, making a hole in the fiberglass insulator bigger. “The hole allowed the arc to catch the plastic radome on fire. As this plastic radome began to burn, melted plastic began dripping down on other plastic radomes causing the fire to spread,” according to Silliman.
Inside Towers reported an ERI crew traveled to the site to determine the cause of the blaze. They measured the damaged antenna and climbed the tower to put pressure caps on some of the coax feeding the antenna. Silliman indicated the antenna would be refurbished and upgraded with flame-retarding plastic radomes.
The master antenna is a 32-bay array on a self-supporting 300-foot tower, Jim Dalke, Editor of the SBE Chapter 16 newsletter told Inside Towers earlier this month. American Tower owns the structure and antenna array.
Inside Towers reported the November 8 fire disrupted transmission for six FMs. KSWD, KBKS, KJAQ, KNUC, KQMV and KZOK are still broadcasting from Aux sites on nearby Cougar Mountain. Comments? Email us.
November 27, 2018
