Another query for you guys: does anyone have any good photos or plans of the SR-3 and SR-6 radars?
Friedman's Naval Radars has the following:
Quote:
SR-3, SR-6
L-band (25cm) long-range air search radars, SR-6 being a lightweight version. Original plans called for cylindrical parabolic antennas, 17ft x 2ft and 10ft x 2ft and 750lb and 500lb respectively, the SRb mattress weighing 711lb. L-band was chosen at the end of World War II to achieve solid radar coverage with a minimum of fading. In this it was successful, but the new antennas chosen performed poorly, one postwar report speaking of 'not enough antenna', for an average range of only 20-30nm - far short of expectations.
At 500kW, and with 4- and 1-microsecond pulses, PRF 150 and 600, SR-3 was to duplicate SK performance, giving 100nm on a bomber at 10,000ft and 80 on a fighter, with a far better beam shape (3 degrees x 65 degrees). Production versions used slotted waveguide antennas with small angled reflectors, SR-3 actually producing a 4 degree x 38 degree beam with a gain of about 200. SR-6, 10ft x 2-1/2ft and 375lb, produced an 8 degree x 34 degree beam of 2-microsecond pulses (PRF 290-310), giving fighter detection at 40nm. Accuracy and resolution of SR-3 were 100 and 200yds, and 2 degree and 1 degree.
The rotation rate of 2.5 or 5rpm was considered too low to counter jets, and both sets had short lives. They were installed as successors to SC and SK during 1947-48, and at the end of 1948 SR-3 was aboard the experimental ship Mississippi, the three Midway class carriers, two battleships, and eleven heavy and five light cruisers, the smaller SR-6 being aboard one light cruiser, one destroyer tender, 38 destroyers, one DDE and two DMs. On 25 April 1948, however, the CNO ordered the replacement of SKs to be stopped in view of deficiencies in the new sets. Existing SR-3s and SR-6s were fitted with the new parabolic SPS-6 series antennas as SR-3B (SPS-6B antenna) and SR-6A (SPS-6A antenna). Alternate modifications were SR-3A (-6A antenna), SR-3C (-6C antenna), and SR-6B (-6B antenna). Other SR-3 modifications included new plumbing and a new pedestal. Westinghouse.
CL-144 was the "one light cruiser" fitted with SR-6 in 1948, as far as I can tell (based on photos of the ship and a mention in Friedman's Cruisers). I can't seem to find good photos of this antenna, though -- anyone have any ideas?
The "antenna catalog" PDF I've found mentions several antennas associated with the SR-3 and SR-6, but sadly the photos are blanked out (likely scanning issue on the original).
SR-3 antennas:- Antenna 66ALN: "collinear array of dipoles with a corner reflector"; description: "The antenna consists of a collinear array of dipoles, mounted on and probe-fed from a 17-1/2 foot section of rectangular waveguide. A V-shaped section of perforated, stainless steel is mounted on the waveguide section to form a corner reflector behind the dipole array. Each dipole is enclosed in a protective cover."
- Antenna 66AMD: "mattress antenna"; description: "The antenna consists of a flat screen reflector with a horizontal row of four dipoles mounted in front of it. The overall antenna is 120-1/4 inches wide by 36 inches high by 16-3/4 inches deep. The total weight is 193 pounds."; Miscellaneous: "The 66AMD is the Mark 3 IFF antenna normally used with Navy Model SR-3 Radar Equipment."
SR-6 antennas:- Antenna 66AMV-(*): "collinear array of dipoles with a corner reflector"; description: "The antenna consists of a collinear of 12 dipoles mounted in and probe fed by a section of rectangular waveguide approximately 9-1/2 feet long. A V-shaped section with a mesh reflecting surface is mounted on the waveguide section to form a corner reflector behind the dipole array. Each dipole is enclosed in a protective cover. The overall antenna is 19-5/8 inches high by 112-3/16 inches long by 23 inches deep, and the total weight is 80 pounds."
- Antenna 66AME: "mattress antenna"; description: "The antenna consists of a flat screen reflector with a horizontal row of eight dipoles mounted in front of it. The overall antenna is 21-3/4 inches high by 66 inches wide by 9-3/8 inches deep. The total weight is 43 pounds."; miscellaneous: "The 66AME is the Mark 4 IFF antenna normally used with Navy Models SR-3 and SR-6 Radar Equipment."
Thanks as always!