I have started on a new model of the AS-1167/SPS-30 antenna for the AN/SPS-30 radar.
Back in 2008 I had only a few distant fuzzy photos to work from and the CAD model was just a place holder until I had better information to work from.
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File comment: The 2008 model.
SPS-30 old.jpg [ 133.56 KiB | Viewed 2912 times ]
I thought the base tower was a two part truncated cone with a cylinder on top of that. In fact the "joint" between the two parts of the cone was a foot rail, and the top was not a cylinder.
The antenna was mounted on two spacer rings at the bottom to raise it high enough that the parabolic reflector dish or the feed horn would not strike the deck at extremes of roll, pitch and elevation. The base tower actually isn't a truncated cone. It is circular at the bottom and more or less square at the top with rounded corners. The foot rail aided working on the mechanism.
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File comment: The new base.
SPS-30 2.jpg [ 49.06 KiB | Viewed 2912 times ]
The base supported a roll platform that pivoted along the fore-aft axis on bearings on the base tower. This was driven by two motors (not modeled yet) that corrected for the ship's roll to keep the antenna horizontal port/starboard. Above this was the pitch platform that pivoted on the port/starboard axis on bearings supported by the roll platform. Again, two motors (not shown) corrected for the ship's pitch to keep the antenna horizontal fore/aft.
The red part is the rotation platform that supported the elevation platform and rotated 360 degrees around the vertical axis on bearings on the pitch platform. It was driven by a large motor (not shown) mounted on the rotation platform. It is red because I have not finished with the basic shapes.
The rectangular box at the top rotated with the rotation platform. It contained electrical slip rings for power and signals to the elevation platform. It also contained the rotating wave guide joint for the radar signals to and from the feed horn.
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File comment: The elevation platform.
SPS-30 1.jpg [ 120.43 KiB | Viewed 2912 times ]
The elevation platform was a large box structure that pivoted on bearings in the rotation platform. A motor (not shown) on the back end of the rotation platform (where the holes are) pulled the cross member up and down to change the elevation of the antenna. The long feed horn and parabolic dish (not shown) attached to the front of the elevation platform.
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File comment: The rotation platform and elevation platform.
SPS-30 3.jpg [ 53.44 KiB | Viewed 2912 times ]
These are just the basic support shapes. There are a lot of details to add. Fortunately, in the past 10 years I have discovered detailed photos and some antenna drawings. I have received quite a few very close up photos of the SPS-30 on the USS
Little Rock CG-5 museum ship by guys who help maintain the ship.
Many thanks to everyone who has helped with this project!
Phil