Sutro Tower facts for kids

Quick facts for kids Sutro Tower
Sutro Tower viewed from Grandview Park in San Francisco
General information
Status	Complete
Type	Radio mast
Location	San Francisco, California
Address	1 La Avanzada Street Clarendon Heights
Coordinates	37°45′19″N 122°27′10″W / 37.75523°N 122.45284°W / 37.75523; -122.45284
Elevation	254.2 m (834 ft)
Completed	July 4, 1973 (July 4, 1973)
Owner	Sutro Tower, Inc.
Height
Antenna spire	297.8 m (977 ft)
Observatory	on Level 6, 228.8 m (751 ft) above base
Dimensions
Other dimensions	base triangle legs spaced 45.7 m (150 ft) on a side waist triangle legs spaced 18.3 m (60 ft) on a side antenna triangle spaced 30.5 m (100 ft) on a side
Technical details
Structural system	Truss tower
Design and construction
Architect	Furman L. Anderson Jr.
Architecture firm	Kline Iron & Steel Albert C. Martin and Associates
Renovating team
Engineer	Simpson Gumpertz & Heger

The Sutro Tower is a very tall, three-pronged tower in San Francisco, California. It stands about 977 feet (297.8 meters) high. This tower is used for broadcasting TV and radio signals.

You can find it on a hill between Twin Peaks and Mount Sutro. It's a famous part of the city's skyline. Many people in San Francisco see it as a landmark.

When it was finished in 1973, Sutro Tower was the tallest building in San Francisco. It held this record until 2017. That's when the Salesforce Tower became even taller.

The tower gets its name from the family of Adolph Sutro. He was a businessman and a former mayor of San Francisco. His grandson, Adolph Gilbert Sutro, built a large house called La Avanzada on their land. This land was on one of San Francisco's highest hills.

In 1948, the property was sold to the American Broadcasting Company. It became the first home for their San Francisco TV station, KGO Television. Later, KGO joined with other major TV stations like KTVU, KRON, and KPIX. Together, they decided to build and take care of Sutro Tower.

The tower stands 977 feet (297.8 meters) above the ground. It is 1,811 feet (552 meters) above sea level. Even though it's not the tallest building by itself anymore, its location on a mountain means it looks down on the city's downtown skyscrapers.

Why Was Sutro Tower Built?

The tower in 2020 during antenna changes.

Before Sutro Tower was built in 1973, getting good TV signals in San Francisco was hard. The city has many hills, and these hills blocked the TV signals. This made TV reception very spotty.

The new tower was built very tall to help solve this problem. Before, TV transmitters were spread out in different places. These included San Bruno Mountain and Mount Diablo. By putting all the main TV station transmitters in one spot, Sutro Tower made things much better. People could now point their TV antennas in just one direction to get all the stations.

How People Felt About the Tower

Some local residents did not like the tower even before it was finished. They worried about how it would look in San Francisco. A famous San Francisco writer, Herb Caen, once joked about it. He wrote, "I keep waiting for it to stalk down the hill and attack the Golden Gate Bridge."

When the tower was first built, its long legs had bright white lights at night. These lights looked like long fluorescent tubes. But many people complained, so the lights were taken down soon after they were turned on.

Even with the early complaints, many people now see Sutro Tower as a symbol of the Bay Area. For example, a local entertainment guide called SF Station uses it as its logo. The collaborative art game SFZero also uses it.

Recent Updates to the Tower

Starting in 2019, one of the three upper antenna parts was temporarily removed. This was to install new antennas. These changes were part of a plan by the FCC to improve how TV signals are broadcast.

The antenna installation was completed on May 1, 2020. For a short time in mid-2020, some stations broadcast from backup antennas. This allowed for final cleanup work on the main antennas.

Building Sutro Tower

Sutro Tower, showing its base.

Construction of Sutro Tower began in 1971. It was built by a company called Kline Towers. The tower was completed in 1973. The first TV signals were sent from it on July 4, 1973.

About 3,750 cubic meters (132,420 cubic feet) of concrete were used for the tower's foundation. The tower itself weighs about 3.7 million pounds (1,700 tons). To protect it from earthquakes, two-thirds of its weight is underground. This means its center of gravity is 16 feet (4.9 meters) below ground.

Sutro Tower is used to send signals for eleven TV stations and four FM radio stations. It also helps with other communication services.

Who Owns Sutro Tower?

Sutro Tower is owned by Sutro Tower Inc. This is a non-profit company. It is owned by a group of the four main San Francisco TV broadcasters. These stations were KTVU, KRON-TV, KPIX, and KGO-TV. They were the biggest TV stations when the tower was built.

Sutro Tower also rents space to other TV and radio stations in the Bay Area. These include PBS station KQED, independent station KOFY-TV, and KBCW. In 2018, San Jose's KQEH also started broadcasting from Sutro Tower.

Some major Bay Area TV stations are not located at Sutro Tower. These include NBC stations KNTV and KSTS, and KTVU's partner station KICU-TV. These stations broadcast from other locations. This allows them to focus their signals on San Jose and the South Bay area. San Jose is the main city they are licensed to serve.

Visiting Sutro Tower

Sutro Tower at night.

Sutro Tower seen above the coastal fog.

Only authorized vehicles can access the Sutro Tower site. However, the areas near the tower offer amazing views of San Francisco.

There is a platform near the top of the tower. It is 761 feet (232 meters) above the ground. It is 1,595 feet (486.2 meters) above sea level. Only authorized maintenance workers can go up the tower. They use a small two-person elevator inside one of the tower's legs. The public is not allowed inside the Sutro Tower property.

On a clear day, you can see the tower from Mount Diablo in the East Bay. Sometimes, when the famous San Francisco fog rolls in, Sutro Tower is the only part of the city that can be seen above it. This often happens on summer mornings and evenings.

Stations Broadcasting from Sutro Tower

Many TV and radio stations use Sutro Tower to send out their signals.

Television Stations

TV stations that broadcast from Sutro Tower include the following. Most of these stations also have extra channels called subchannels.

Radio Stations

FM radio stations that broadcast from Sutro Tower include:

• KOIT (96.5)
• KSOL (98.9)
• KOSF (103.7)
• KNBR-FM (104.5)