Specifications

2-19. HOMING SENSITIVITY TEST. (CONT)
EQUIPMENT
TS-2575/ARC-131
AN/URM-103
CONTROL AND SWITCH SETTINGS
CONTROL OR SWITCH
MODE SWITCH
SQUELCH
FREQ sel
LEFT and RIGHT HOMER ATTEN
BAND SWITCH and RF TUNING control
FUNCTION switch
RF OUTPUT switch
LO-HI RF SET to LINE control and
LO RF UV
TM 11-5820-670-30
POSITION/SETTING
HOME
CARR
31.00 MHz
0
Adjust to 31.00 MHz.
MOD OFF
LO 0-10 KUV
Adjust as required in
procedure.
TEST PROCEDURE
1. Increase AN/URM-103 output by adjusting LO RF UV control until flags on homing Indicator
lD-48A/ARN disappear.
2. Divide by two the AN/URM-103 dial indication observed in step 1.
STANDARD. 1.2 microvolt maximum
3. If quotient is more than 1.2 microvolt, see troubleshooting chart 2-22.
4. Repeat steps 1 through 3 adjusting test set for frequencies of 50.50 MHz and
68.95 MHz.
5. Set test set LEFT HOMER ATTEN control to 3 db and RIGHT HOMER ATTEN to 6 db.
6. Adjust AN/URM-103 Attenuator control for a 12 microvolt output signal.
7. Set frequency selectors to 31.00 MHz and tune AN/URM-103 to receiver frequency. Ob-
serve and record deflection of lD-48/ARN vertical needle.
STANDARD. Left length of wing minimum
8. If deflection of vertical needle does not meet requirement of the standard, see trouble-
shooting chart 2-23.
9. Reverse db settings of RIGHT and LEFT HOMER ATTEN. Record needle deflection.
STANDARD. Right length of wing minimum
10. If deflection of needle does not meet requirement of the standard, see troubleshooting
chart 2-23.
11. Repeat steps 5 through 10 adjusting frequency selectors of test set for frequencies of
50.50 MHz and 68.95 MHz.
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