Early Navy air radars were designated in the same manner (but not the same series!) as the surface sets, so that ASH was the eighth airborne search radar. Even during the war it proved difficult for Navy and Army (Air Force) to coordinate airborne radar procurement. The fragmented system thus described did not long outlast World War II. One Army radar, SCR-720, was fitted in limited numbers to US warships at the end of the war. The Army used an entirely different class of designations, its radars being numbered in the Signal Corps Radio (SCR) series. These series included all types of electronic equipment. The prefixes 'X' and 'CX' were reserved for the Navy (NRL) and commercially produced experimental or preproduction sets, eg CXAM, the first US naval radar. Lower-case letters ( eg 'a' in SRa) indicated field changes.

There were only twenty-four search radars, so none required three letters. Three letters were generally used to extend series beyond twenty-five (the letter I was not used) thus RAA, RAB and RAG would be the twenty-sixth, -seventh, and -eighth radio receivers. Such designations were dropped early in the war, but persist on plans drawn as late as 1945. However, the earliest fire control radars were also designated under the BuShips system, with the type letter F thus FH is Mark 8. The Bureau of Ordnance preferred to use mark numbers, eg Mk 25 modifications within a mark were also numbered, eg Mk 25 Mod 1.

The former carried over a system consisting of a type letter, eg S (search radar), and a model letter: thus SC is the third US search radar and SC-S is the fifth modification of SC. During World War II, the US Navy deployed two major radar series: search sets (BuShips) and fire control systems (BuOrd). These reflect the organizations behind development. The history of US naval radars is somewhat confusing because of the variety of types of designations employed.

Navy radar room team world war 2