U.S.S. Allen M. Sumner DD-692
Sensor Systems

The Sumner carried a wide variety of systems designed to sense the enemy by radio waves, sound waves and electrical impulses. These included Radar, Sonar and Electronic Counter Measures (ECM). The following is a brief introduction to these systems and views as they appeared on board. We lack the expertise to properly complete this part of our story and solicit your comments, photographs and guidance.

RADAR

SC and SG Radars

The initial RADAR installation on the Sumner consisted of the SC "Sugar Charley" and SG "Sugar George" series radars. The "Sugar Charley" was for Air Search with a range of 80 nautical miles at a 10,000 foot altitude. It used a 15 X 4 foot horizontally polarized mattress type antenna with an array of dipoles. One of the improvements to this radar was the installation of a 10 X 2 foot mattress fitted atop the main antenna with additional dipoles.  The "Sugar George" radar was a surface search radar also used a horizontally polarized antenna and used a solid 5 X 1.75 foot parabolic reflector. It could detect surface contacts at 20 nautical miles and aircraft at 15 nautical miles up to 500 feet in altitude. It also displayed land masses and was therefore useful in navigation.

	The SC2 modules.

SPS-6

In the early 1950's the "Sugar Charley" Air Search radar was upgraded by installation of the SPS-6 which used a 6 X 17 foot parabolic reflector with a wind balancing vane fitted on the back. While the useful range remained at 80 nautical miles it could detect aircraft to 40,000 feet in altitude at that range.

SPS-10

In about 1953 the "Sugar George" Surface Search radar was replaced with the SPS-10 which was a high resolution lightweight unit. The antenna was a 10.25 X 2.75 feet mesh parabolic reflector with two dipoles for the IFF (Identification Friend or Foe) located around the feedhorn. The SPS-10 could track a submarine periscope at 16,000 yards. This unit remained aboard throughout the rest of Sumner's active service. It can be seen in the above photographs and in those that depict the SPS-40 below. 

SPS-40

During the FRAM II period overhaul the SPS-6 Air Search radar was again upgraded to the SPS-40. It used a 10.5 X 3.5 foot parabolic reflector which incorporated the IFF system. This radar could detect targets beyond 200 nautical miles at altitudes of 50,000 feet. This unit served the Sumner until her decommissioning.

SONAR

QGA and SQS-4

The initial SONAR system installed in the Sumner was the QGA which used a transducer mounted under the keel protected by a 100 X 26 X 60 inch tear shaped free flooding steel dome. It also had sound absorbing baffles mounted at the aft end to prevent picking up the Sumner's own propeller noise. The ranges in recorder mode were 1,500 and 3,750 yards. In manual search mode they were 3,000 and 5,000 yards. We do not have any photos of the QGA system as it appeared on the Sumner. During FRAM II the system was upgraded to the SQS-4. The transducer for the SQS-4 was protected by a 102 inch long by 51 inch deep dome. The range scales possible with this unit were 1,000; 2,500; 5,000; 10,000 and 15,000 yards.

 VDS
SQA-8 VDS Hoist-Transducer / SQA-10 VDS Hoist

During the winter of 1962 the VDS (Variable Depth Sonar) system was installed. This Sonar was designed to detect targets that could evade detection by using the thermal layers within the ocean. The towed unit contained a modified version of the SQS-4, the SQS-31 or SQS-32. The cable drum held 600 feet of tow cable. The length paid out and the speed of the ship controlled the depth at which the VDS operated.

ELECTRONIC WARFARE

ESM/ECM

Electronic Warfare is used to interfere with the enemies weapons systems. ESM is Electronic Support Measures while ECM is Electronic Counter Measures. These systems began to be deployed in late 1944 beginning with the SPR-1 and SPR-2 ESM systems but it is unclear what systems were actually installed on the Sumner and when. We could use some expertise from you ET's on this! It appears that the Sumner did employ the WLR-1 ESM System in the 1960's with the two outboard "black derby" antenna pots each containing an NT66131 ECM antenna and an NT66132 ECM antenna. The central and higher "black derby" contained the AS-570/SLR ECM antenna.

Many thanks to Don Marion, Gary Vogel, George Aichele, Eric Bollin, Paul Delasco, Bob Misiano, Jan Tenhoeve, Dolphus Burton, Jim Poston, Tom Schwartz, Carlo Martinelli and Hank Lunki for sharing these pieces of Sumner history.