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“I had no idea we had an antenna problem driving to the site because as far as I could tell, we were on the air. The audio in my car was perfect.”

-Buzz Anderson, KRKO Engineer
 

KRKO Antenna after collapse

KRKO Antenna after collapse


 
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“Nautel transmitters are bulletproof and they kick ass.”

-Andrew Skotdal, President
 
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Nautel’s XR50 Handles KRKO-AM Antenna Destruction with Finesse – NEVER Leaving the Air

 

Friday morning, September 4, 2009 – vandals claiming affiliation with the Earth Liberation Front destroyed KRKO-AM’s brand-new, 50,000 watt directional antenna system using an excavator. Telemetry from the site poured out of the remote control around 2 a.m., and by 3 a.m. Buzz Anderson, KRKO’s engineer, arrived to find dozens of patrol cars, K-9 units, and two out of four radiators on the ground, including the 350-foot primary radiator. The 3 1/8″ transmission line feeding the main radiator and the 1 5/8″ line feeding the first radiator were essentially reduced to open conductors while RF continued to flow into all four transmission lines, including to the remaining two radiators on site. All contactors in the system remained in the directional position leaving the transmitter exposed to the damaged transmission lines and the remaining two antenna tuning units.

Nautel’s XR50 handled the event with finesse and NEVER left the air. Despite two out of four towers in the 50,000 watt nighttime array being toppled, the XR50 gracefully scaled back and maintained 4.5 kW of power and a crystal clear signal from the remaining two radiators of the directional antenna. Anderson stated, “I had no idea we had an antenna problem driving to the site because as far as I could tell, we were on the air. The audio in my car was perfect.”

Nautel XR50 and XR12 (main/backup) at KRKO-AM

Nautel XR50 and XR12 (main/backup) at KRKO-AM

KRKO personnel switched over to the circa 1959 former 5,000 watt site that morning to allow forensic teams from the Federal Bureau of Investigation to comb over the site for clues. While television news crews circled in helicopters, station staff used the opportunity to reset system contactors at the damaged antenna tuning units and inspect the transmission system, including the transmitter. A quick dummy-load test of the XR50 at full-power confirmed the transmitter remained in perfect working order and was ready to go again at 50,000 watts.

What the bad guys didn’t know (nor did the general public) was that the KRKO site was developed with the ability to operate omni-directionally from more than one radiator. The KRKO “disaster design” was conceived to address a potential large earthquake within a short distance of the transmitter site where one or more radiators suffered catastrophic damage. That design paid big dividends when it came time to fire up the XR50 after the “all-clear” was given by federal officials. A simple push of a button connected the XR50 transmitter with one of the remaining radiators in omni-directional mode. The fault light on the XR50 transmitter extinguished to acknowledge that the transmission path was ready to go, and seconds later, KRKO was back on the air from the site of the attack at full-power.

KRKO’s owner, Andy Skotdal, states, “I can’t express how impressed I am by Nautel’s transmitter design. Most other transmitters would have either shut down or melted down in flames taking the transmitter building with it. Our Nautel XR50 simply scaled back until it found an antenna load that worked and continued to perform for over an hour until we switched to our aux site. We’re so thrilled with our Nautel XR50 transmitter, we purchased a second XR50 for our new AM station we’re constructing this summer.” And, alongside each XR50 at the KRKO transmission site is a Nautel XR-12 serving as a spare transmitter underscoring the importance of the phrase, “Plan for the worst, but hope for the best.” Skotdal adds, “Nautel transmitters are bulletproof and they kick ass.”

Andrew Skotdal
President
KRKO-AM