Mk 54 STIR
This system was developed from the AN/SPG-60 and is very close to it in looks but is slightly bigger.
The STIR is part of the Mk 92 FCS and Mk 87 FCS the STIR antenna can track targets at longer range then the antenna embedded in the CAS (Combined Antenna System, the famous egg) of these fire control systems due to it's larger diameter dish. The antenna can operate in CWI mode to guide standard MR missiles. The STIR is fitted with 2 alignment telescopes which see trough holes in the antenna. The dish is also pierced for an Coaxial television tracker but this was not fitted as build.
The antenna design is designated UD 417, the system is sometimes designated the Mk 54 but more often it is just designated as the STIR.
The STIR is an option for the US fire control systems derived from the Dutch WM-20 series, specifically the Mk 92 and 87. It adds additional guidance channels for air targets to the system and increases the guidance range. This means it is often only worth it on bigger ships with air defence missiles, most notably the FFG-7 Perry class frigates.
Control cabinets and other systems are required belowdecks to use this system but no exact dimensions are known. Their placement is independent of the antenna.
The STIR has been in use from 1977 until 2015 in the USN (although many ships had their STIR removed when their Mk 13 GMLS was decomissioned), until 2019 in the Australian Navy and is still in use on the exported Perry class frigates in the RoC navy and Spanish navy.
- Perry class
The component is drawn including top views, sideviews and front view. There is no deck penetration to speak off under then antenna itself, but power control, antenna control, signal data converter, receiver and transmitter units are required belowdecks for this component to function.