Up-Converter Input Signal Level Change Procedure

TM 11-5895-833-12/NAVELEX 0967-LP-550-1010/TO 31R5-2TSC54-91

down-converter in the cabinet, slide the

3-10. Up-Converter Input Signal Level

down-converter out of the cabinet, loosen

Change Procedure

the captive screws securing the side cover to

the down-converter, and remove the side

a. Set RF OUTPUT switch to OFF-LINE.

cover. If the filter is changed, make certain

b. Set STATUS SELECTOR switch to 70 MHz IF and

that the placarding on the front of the unit

set IF LEVEL ATTENUATOR switches for center-scale

agrees with the filter installed.

indication on STATUS meter.

c. Observe that the RF LEVEL indicator lamp is

(2) Set POWER ON-OFF circuit breaker to ON and

extinguished.

observe that the POWER ON indicator lamp illuminates.

d. Set STATUS SELECTOR switch to each position in

(3) Set STATUS SELECTOR switch to RF LO

turn and observe the following indications on the

TUNE and adjust RECEIVE FREQUENCY FINE TUNE

STATUS meter:

control for a center-scale indication on STATUS meter.

(4) Set RECEIVE FREQUENCY SELECTOR MHz

Position

Indication

thumbwheel switch to new operating frequency.

70 MHz IF

Blue scale

700 MHz IF

Blue scale

(5) The RF LO indicator lamp will illuminate and the

+ 24V

Green scale

audible alarm sounds when the frequency change is

RF LO TUNE

Red scale

greater than 6 to 10 MHz.

STD LVL

Blue scale

(6) Press and hold AUDIBLE ALARM DEFEAT

RF LO

Blue scale

pushbutton, if necessary, and adjust RECEIVE

IF LO

Blue scale

FREQUENCY FINE TUNE control for a center-scale

indication on STATUS meter.

e. Set RF OUTPUT switch to ON-LINE.

(7) Release

AUDIBLE

ALARM

DEFEAT

pushbutton and note that the audible alarm is silent.

3-11. Up-Converter Output Signal Level

(8) Observe that the RF LO indicator lamp is

Change Procedure

extinguished.

a. Set RF OUTPUT switch to OFF-LINE.

NOTE

b. Set RF OUTPUT LEVEL ADJ to new setting.

Set the MODE SELECTOR switch to

c. Set RF POWER meter upper and lower limit

FM or DGTL, depending upon the re-

controls to position pointers at 1-db points on either side

quired carrier operation.

of new output level.

d. Observe that the RF LEVEL lamp is extinguished.

(9) Set STATUS SELECTOR switch to each

e. Set STATUS SELECTOR switch to each position in

position in turn and observe the following indications on

turn and observe the following indications on the

the STATUS meter:

STATUS meter:

Position

Indication

Position

Indication

+ 24V

Green scale

700 MHz IF

Blue scale

STD LVL

Blue scale

700 MHz IF

Blue scale

RF LO

Blue scale

+ 24V

Green scale

IF LO

Blue scale

RF LO TUNE

Red scale

700 MHz

Approximately 0 to 3

STD LVL

Blue scale

700 MHz

Varies with input signal

RF LO

Blue scale

level (applies to down-

IF LO

Blue scale

converter (wide-band if.)

only)

f. Set RF OUTPUT switch to ON-LINE.

70 MHz IF

Varies with input signal

level

3-12. Equipment Shutdown Procedure

RF LO TUNE

Red scale

Stop the frequency conversion subsystem by turning off

NOTE

all equipment except cesium beam frequency standard.

The 700 MHz IF and 70 MHz IF positions of

the STATUS SELECTOR switch are used

primarily for maintenance caused by the

signal levels required to scale the STATUS

meter in these positions.

Change 1 3-20.1