The Exploratorium made this fascinating 10-minute video about one of SF's most recognizable, but least understood landmarks, Sutro Tower. If you don't have patience to watch all of it (TL;DW), I've pulled out the most interesting factoids that the video highlights, so you can sound smart the next time a visitor asks you what Sutro Tower is all about: 

  • Sutro Tower is basically a huge antennae that transmits and receives radio, TV, and other wireless signals, including those used by law enforcement, taxi companies, other transportation users, and emergency services. 
  • The land it's built on, one of the highest peaks of San Francisco, was owned by the wealthy Sutro family, who built a mansion on the hill (and yes, who also built the Sutro Baths). ABC bought the land from the family in the 1940s, built a 500-ft. high tower, and used the mansion as its studio. Unfortunately, 500 feet was not tall enough, and reception was pretty spotty. 
  • Construction of the Sutro Tower as we know it began in 1971; it was officially open on July 4, 1973. It is 977.25 ft. high; it needs to be so tall in order to send signals throughout the nine counties of the San Francisco Bay Area.
  • Its hourglass design was built to withstand huge earthquakes and really strong winds, both of which are pretty realistic threats in SF. If for some reason Sutro's generators went down, there are back-up generators in place. 
  • When it first went up, many locals weren't sure of its retro-atomic look; they thought it was a huge eyesore and shouldn't have happened. Herb Caen once said that when Sutro Tower is almost completely engulfed in fog, with only the tippy top showing, it looked like a sailboat sailing on top of the fog.
  • There are two ways up the tower, and neither are for public access – in a hoist, and in a tiny elevator, which is only 27" by 33;" it takes eight minutes to go up 750 feet to the sixth level.  
  • There are 249 antennae on Sutro Tower, with KGO Channel 7 having the highest and best position on it, which means it has the strongest signal in the Bay Area. TV stations try to be up top so they can reach more people. 
  • The city of SF regulates the structures and antennas placed on Sutro, but the transmissions are regulated by the FCC.
  • In case you were worried about radiation coming from Sutro: Radio frequency energy (non-ionizing radiation) isn't the kind that's super dangerous (nuclear decay radiation). You are exposed to much more radiation from the sun than from Sutro Tower.

[Via: Exploratorium; photos by Sierra Hartman]

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