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Did You Know

Did You Know – What is that Dome Structure?

Have you ever been traveling out to Cabrillo National Monument and wondered what that dome shaped framework structure was along the road? How about that large round “swimming pool” off to the side? And what about all those model ships that are near the Federal Firestation?

These are some of the questions Cabrillo volunteers get asked while working out at Cabrillo. Well we have those answers for you.

Let’s start with that dome structure that can been seen for miles on top of the Point Loma peninsula.

The image shows an aerial view of a complex with several buildings and structures. The most prominent feature is a large circular area in the center, which appears to be a large dish or platform, possibly part of a radar or satellite installation. Surrounding this central structure are multiple buildings with red roofs. The area is bordered by roads, with "Cabrillo Memorial Dr" being the main road visible in the image. The landscape around the complex is hilly and covered with vegetation. There are also parking areas with several vehicles parked. The overall setting appears to be a mix of industrial and natural elements.
Google

This dome structure and the large brass model ships that are seen behind the fence are actually related.

The image shows a large, white, metal arch structure set against a clear blue sky. The arch is tall and has a lattice-like design, with visible cross-bracing. In the foreground, there are green trees and bushes, and a building with a red roof. In the background, there are more trees and some additional buildings. The overall setting appears to be an outdoor area, possibly a park or a facility with open spaces.
NPS Photo/D. Wieder
The image shows a fenced area with a chain-link fence in the foreground. Inside the fenced area, there are several metal structures and equipment, possibly related to industrial or utility purposes. The ground is dry and covered with brown grass or dirt. In the background, there is a small building with a red roof and beige walls. The area is surrounded by some greenery, including trees and bushes. The sky is clear and blue, indicating a sunny day.
NPS Photo/D. Wieder

The dome structure is called the Shipboard Antenna Model Range. It was one of the first structures built by the Naval Electronics Lab (now called NAVWAR) in 1945. NAVWAR has changed names over the years but the general mission has stayed the same. The history of NAVWAR on the Point Loma peninsula has a remarkable story and that will be detailed in a future post.

The non-metallic arch of this structure supports a transmitting antenna which is positioned toward a brass model ship on a turntable. The ground plane under the arch simulates the electrical characteristics of the ocean, allowing research on the properties of shipboard antennas to be studied. The brass model ships are placed in the center under the arch to test various antennas.

The image shows a collection of model ships behind a chain-link fence. The ships appear to be detailed replicas, possibly of military or naval vessels, and are placed on wooden supports. The area around the ships is covered with dry grass or straw. In the background, there are more model ships and some greenery, indicating that this might be an outdoor display or storage area.
NPS Photo/D. Wieder
The image shows a fenced area with a chain-link fence in the foreground. Behind the fence, there are several metal structures and equipment, which appear to be old or unused. In the background, there is a small beige building with a red roof and a blue sign that reads "A306." The area is surrounded by trees and greenery, and the ground is covered with dry grass and straw. The scene appears to be an outdoor storage or maintenance area.
NPS Photo/D. Wieder
The image shows an outdoor area enclosed by a chain-link fence. Inside the fenced area, there are several large, gray, model ships. The ground inside the fence is a mix of dirt and sparse grass. In the background, there are a few buildings, one of which has a reddish-brown roof and another with a sign that reads "A300." There are also some trees and bushes around the area, providing some greenery. The scene appears to be taken on a sunny day, with shadows indicating the position of the sun.
Google

The model ships are built out of wood and brass.

The image shows a man standing outdoors on a paved surface, working on a large, detailed model of a ship. The man is wearing a short-sleeved, red and white striped shirt and light-colored pants. He appears to be adjusting or assembling parts of the ship model, which is predominantly golden in color and has intricate details, including various structures and masts. The background is somewhat blurred, but it shows an open area with some trees and power lines in the distance. The sky is clear, suggesting it is a sunny day.
spawar.navy.mil/sandiego/anniversary/
Two men kneel next to a brass model navy ship on a concrete pad.
Photo from: https://navy-radio.com/ant-ship.htm
Four men stand behind a model navy ship in a workshop
240222-N-ZB499-1021 SAN DIEGO (Feb. 22, 2024) From left, Fred Blas, Bob O’Neill, Jun Peralta, modelers retired from Naval Information Warfare Center (NIWC) Pacific, and Ben Wong, modeler at NIWC Pacific, pose behind a brass model of USS Arleigh Burke (DDG 51) in the ship model shop at NIWC Pacific in San Diego, Feb. 22, 2024. Among the four of them, Wong and his predecessors have ruled the Center’s ship model shop for half a century, where they’ve built dozens of brass model ships used for validating antenna configurations on real Navy ships 48 times the models’ size before any metal is cut in the shipyard. (U.S. Navy photo by Aaron Lebsack). Photo from https://navy-radio.com/ant-ship.htm

Read more about one of these model ship builders who carries out the work today.
Press Release – 1949

If you stop at one of the pull outs along Cabrillo Road, you will see something that looks like a large circular swimming pool. Visitors at Cabrillo often ask what that structure is, as it seems out of place with the surroundings.

The image shows an aerial view of a coastal area with a large circular structure that appears to be a water tank or reservoir. The structure is surrounded by several buildings and roads. Key features: - The circular water tank is centrally located and has a platform or structure extending over it. - Surrounding the tank are various buildings, including one labeled "Building 609." - A road named "Cabrillo Memorial Dr" runs horizontally across the bottom of the image. - The area is hilly with patches of vegetation and rocky terrain. - In the background, there is a body of water, likely the ocean or a large bay.
Google

This is part of the Arctic Submarine Laboratory, also part of NAVWAR. The Arctic Submarine Laboratory is a research facility. It began as a converted World War II mortar emplacement, Battery Whistler. The Submarine Lab’s mission is focused on scientific exploration of the Arctic Basin, and particularly providing the capability to operate attack submarines in the Arctic under the ice canopy.

A large concrete open basement
Battery Whistler in 1948, Public Domain

The pool was constructed to test equipment for deep submersible vehicles. The pool is equipped to grow sea ice and study its physical properties. The Lab continues today with its primary missions, developing new technology for the use of US submarines heading under the polar ice pack and providing operations staff to assist in taking submarines under the ice pack.

So this pool is not used for swimming, although it certainly looks inviting on a warm, clear sunny day.

The image shows a large, circular pool of water with a structure in the middle that has the letters "SCC" prominently displayed. The pool is surrounded by a paved area and some buildings, likely part of a facility. In the background, you can see the ocean extending to the horizon under a clear blue sky. The foreground has some bushes and vegetation. The overall scene appears to be a coastal research or industrial facility.
NPS Photo/D. Wieder

And that is just a little history of some of the NAVWAR structures along Cabrillo road. Next time as you drive out to the park, you will have a better understanding of the structures that are visible. You will hopefully be able to explain to visitors about their significance to the area too.

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