ST, STa, ST-1 SEARCH RADAR


ST periscope antenna.
ST periscope antenna.

Description.-A 3 cm. range-determining radar for submarine installation.
The antenna is mounted in the periscope and is intended for use at periscope depth. STa is a modified ST, periscope adapter and wave guide switching unit. Accomplished in the field.
ST-1 is a modified ST, periscope adapter and wave guide switching unit, plus SS units. Accomplished by manufacturer.
When SS is available, the SS transmitter will feed directly into the ST-type antenna. This arrangement will be known as STa if modified in field, as ST-1 in new manufacture.

Number of operators.-One.

Weight installed.-500 lb. excluding indicator.

Power supply.-1.5 kva, 115 volts, 60 cps, 1 phase.

Maximum reliable range (miles):
  Battleships     5
  Cruisers        5
  Destroyers      3
  Submarines      3
Minimum range 250 yds.
Resolution:
  Range          75
  Bearing        20
Accuracy:
  Range (yd.)    15+-0.1%
  Bearing       +-5 degrees
Indication and data output:
Range: 5-inch A scope of SJ or SS indicator.
Ranges: 10, 30 miles.
Bearing: Bearing dial.
PPI: None. Provisions for IFF display. The ST uses the same indicator as the SJ or SS.
Antenna specifications:
  Total weight (lb.)      Periscope, 2000 lb.;
                           adapter unit, 300 lb.
  Feed 2-inch by 6-inch horn mounted in the periscope.
  H.P. beam width:
    Horizontal            25 degrees.
    Vertical              12 degrees
  Polarization            Horizontal
  Gain (db)               15
  Scan                    By hand.
Antennas height is variable from 1 to 50 ft.
Transmitter specifications:
  Frequency (Mc)         10 000.
  R-f source             Magnetron, 2J50.
  R-f lines              Wave guide.
  R-f peak power (kw)    30.
  R-f average  power     0.03.(kw).
  Pulse rates (pps)      1500+-150; 600+-30.
  Pulse lengths (micro second) 0.25.
Receiver specifications:
  Type                         Superheterodyne.
  Local oscillator             723.
  Intermediate frequency (Mc)  60.
  Band passe (Mc)              3 i.f. with SJ; 4 i.f. with SS.
  Mixer                        1N21A.
  Noise, db above theoretical  14.6.
Tube complement.- 1 type 2J50; 1 type 705A; 2 type 724B; 1 type 5021; 1 type 6H6; 4 type 6V6-GT; 10 type 6SN7GT; 1 type 723A/B; 5 type 6AK5; 2 type VR15O/30; 4 type 991 (NE16); 8 type 6AC7; 1 type 2X2/879.
         Dimensions and weight
       Unit             Navy Type Height  Width     Depth     Weight  Pampanito
                           No.    Inches  Inches    Inches    Pounds  Serial #
Selector unit             24AAH   14 3/4   16 9/16   16 13/16  95    #166,C.T.
Transmitter receiver      43ACU   19 1/2   15 11/16  27       230    #166,C.R.
Selector control unit     23AFP    4 5/8    7 7/8     3 1/2    15    #178,C.T.
Periscope adapter         14ABB   48       18 dia.   18       300
Wave guide switching unit 24AAF    3 7/8   10        11 1/2    20    C.R.
Echo box                  14AAX   15       18 7/8    16 1/4    40    C.R.
Wave guide pick-up        l4ABJ    3 7/8    8 1/8    11 1/8    16    C.R.
Junction box              62ABK   17 9/16  13 1/4     4 7/8    40    C.R.
Dummy antenna             66AHT    1 3/4    7 13/16   2         8    C.R.
Transmitter mtg. frame    10376   27 15/16 19 1/8    13 19/32  80    C.R.
Literature.-Instruction book (NavShips 900,336-IB).

REFERENCES:

The information enclosed here is excerpted from:
Catalogue of Naval Electronic Equipment-April 1946- NavShips 900,116.

 

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Version 2.00, 11 Sep 2006