DESCRIPTION AND OPERATION
1. GENERAL
This manual contains maintenance, and overhaul instructions for the ADF-T-12B,C Automatic
Direction Finder System. The manual contains five sections; Description and Operation,
Maintenance Practices, Illustrated Parts Breakdown, Schematics and Addenda.
A.
The ADF-T-12B,C System functions as an airborne automatic direction finder or as arange and
broadcast band receiver. Three tuning bands provide continuous frequency coverage from 190 to
1750 kilocycles. During ADF mode of operation, the system may be used to either home on astation
or to obtain aposition fix. Directional information is displayed on apanel-mounted indicator.
B.
The system comprises three principal components (See Figurel). They are as follows :
C.
( 1 ) M o d e l 2 0 1 ( ) R e c e i v e r
(2) Model 551A Servo Amplifier-Indicator, Model 551B Remove Gonio Synchro, Model 551C Dual
Synchro Indicator, Model 551E Servo Amplifier-Indicator.
( 3 ) M o d e l 2 3 2 I E F i x e d L o o p A n t e n n a .
D. MODEL 201 RECEIVERS
T h e d i ff e r e n c e s b e t w e e n t h e v a r i o u s M o d e l 2 0 1 R e c e i v e r s c o n s i s t s o f :
(1)
R e c e i v e r l e s s C W o s c i l l a t o r
R e c e i v e r w i t h C W o s c i l l a t o r
N a r r o w B a n d R e c e i v e r l e s s C W o s c i l l a t o r
N a r r o w B a n d R e c e i v e r w i t h C W o s c i l l a t o r
Narrow Band Receiver with built-in tuning meter less CW oscillator
Narrow Band Receiver with built-in tuning meter with CW oscillator
Model 201A
Model 201B
Model 201A-1
Model 201B-1
Model 201C
Model 201D
The 1000 cps CW oscillator is used for each tuning-in of distant or weak stations. Afourth
position (CW) on the function selector switch is available on the applicable models which have
the 1000 CW oscillator.
(2)
The tuning meter, included on Models 201C, DReceivers, is used to indicate peak signal
strength for individual stations.
(3)
Aspeaker amplifier is available as optional equipment. The amplifier (Model 102A,B) is mounted
separately at aconvenient location in the aircraft.
E.
Aterminal at the ADF receiver connector is provided for connecting dry-cell batteries for emergency
operation.
F.
2. D E S C R I P T I O N O F C O M P O N E N T S ( S e e F i g u r e 1 )
A. FIXED LOOP ANTENNA
The Model 2321E Fixed Loop Antenna consists of two insulated coils, wound at right angles to
each other on aflat ferrite core and terminated at a7-pin socket connector. The loop is rec¬
tangular in shape and mounts externally on the aircraft. The assembly is sealed in potting
compound making it impervious to extreme environmental conditions. The unit is sprayed
w i t h a n t i s t a t i c p a i n t .
(1)
The wavefront of the station-transmitted radio wave intersects the lateral and longitudinal coils
of the fixed loop antenna and induces voltages in each of them. In relation to the aircraft, these
voltages are proportional in amplitude to the angle of arrival of the radio wave with respect to
the position of the aircraft.
(2)
April 1965
(Revised October 1969)
Page 1
To Next Page
Loading...
General