Radio Navigation Equipment - Signalspaning.se

Radio Set AN/CRT - 3 is an air-transportable,
hand-powered emergency transmitting system designed for
operation from a rubber life raft and to serve as an aid to
sea rescue. It consists of a modified SCR-578-A and operates
on the international distress frequency of 500 kc.
AN/CRT-3 also operates on a frequency of 8280
kc. with a 1000 cycle MCW note on 500 kc. and CW emission
only on 8280 kc. Transmission is automatically shifted
every 40 seconds from one frequency to the other. Operatibnal
manual keying on the international distress frequency
is provided. When manually keyed, the transmitter oper -
ates only on the international distress frequency. The frequency
shifting mechanism is then inoperative.
Use of 8280 kc. provides a means of obtaining
long range bearing from landbased direction linding stations
so that ships or aircraft can be dispatched to the general
location, and the 500 kc. transmitter is used by the rescue
craft to home on the life raft. On test using the 8280 kc.
frequency, satisfactory bearings have been obtained up to
1,600 miles. Included in the equipment is a parachute to
permit dropping of the set into the sea without damage.
Test equipment for maintenance is under development.
Army Supply Program requirements for AN/
CRT-3 and/or SCR-578 as of 31 October 1944 were 40,742
equipments for the calendar year 1944 and 43,023 for 1945.
POWER INPUT HAND CRANKED
FREQUENCY 500 KC. & 8280 KC.
TYPE OF SIGNAL MCW FOR 500 KC. CW
FOR 8280 KC
RANGE 200 MILES AT 500 KC.
1600 MILES AT 8280 KC
DUAL FREQUENCY 40 SECONDS
AN/ CRT-3
Radio Set AN/CRT-3 packed with parachute M-340-A attached.
TUBE COMPLEMENT
NO. TYPE I NO. I TYPE
1 12A6 1 12SC7
Front View of Radio Transmitter T- 74(XA-A)/CRT-3(XA-2)
Nay 1945