Radar Technology at Mill Valley
When MVAFS began operation in 1953, the PERMANENT radar system installation, which was common to at least 75 other stations, consisted of two radars - a search radar and one height finder radar. The search radar turned inside a "radome" or domed tower. The height finder was located outside. The search radar at that time may have been a CPS-5 radar in Building 409. This was replaced by an FPS-7 radar which remained in Building 409 until the FAA moved in, about 1982. At that time, an FPS-66A radar was installed. This is still in operation.
The first height-finder radar was an FPS-6 which was an outdoor radar located on the main terrace. In 1962, this was moved to a position outside the current gate, on the slope below the terrace. In this position, it was modified to an FPS-90 and back to an FPS-6. In 1961-1963, a second height-finder radar, an FPS-26, was installed in the new radome tower, Building 411. Until 1982, there were two height-finder radars at MVAFS, the FPS 690 outside the gate, and another one inside Building 411. In 1968, the FFS-7 radar for SLBMs was installed in Building 411, and the FPS-26 was removed. In 1982, the FFS-7 was removed, and since that time, Building 411 has been empty.