T-1654(P)/GRC-144V) and T-1054(P)A/ GRC-144(V) Modulator Frequency Adjustment

TM 11-5820-695-35

ab. Set the meter switch an the radio test set to

On R-1467(P)/GRC-144(V) turn the AGC

OSC LEVEL and adjust the LEVEL ADJ control on 100

SEL switch on 70 MHz intermediate frequency amplifier

2A5 to TEST and turn meter selector switch 2A15A2S1

MHz radio frequency oscillator '1A2 for a set OSC

LEVEL ADJ indication on the radio test set meter.

on meter panel assembly 2A15A2 to CARRIER (IF).

ac. Using a screwdriver. turn the ATTEN ADJ

Remove the dust cover from the ATTEN

control on Coupler, Directional CU-1890/ GRC in a

ADJ control on Coupler, Directional CU-1890/ GRC and,

clockwise direction until meter 2A15A2M1 on meter

using a screwdriver, turn the ATTEN ADJ control

panel assembly 2A15A2 indicates 150.

clockwise until mechanical stop is reached.

ad. Replace the dust cover on Coupler,

NOTE

Directional CU-1890/GRC ATTEN ADJ control.

If meter 2A15A2M1 is off scale,

ae. Set the ON/OFF switch on 100 MHz radio

reduce the POWER SET control on

frequency oscillator 1A2 to OFF.

AN/URM-52B for an on scale meter

reading. After performing step ' g,

af.

Set the AGC SEL switch on 70 MHz

increase POWER SET control for a

intermediate frequency amplifier 2A5 to DIV OFF.

dial scale indication of -71 dbm.

ag. Reconnect the antenna waveguide to the rf

Fine tune the SIGNAL FREQUENCY control

entry panel on the external shelter wall.

on AN/URM-52B for a peak indication on meter

ah. Reset the controls on T-1054(P /GRC-

)

2A15A2M1.

144(V) and R-1467(P)/GRC-144(V) to the original

Remove the green cap from the IF GAIN

operating frequencies.

control on 70 MHz intermediate frequency amplifier 2A5

ai.

Set Switch, Waveguide SA-1679/GRC to

and, using the tuning tool, adjust the IF GAIN control

the TO ANTENNA (NORMAL) position.

until an indication of 150 is observed on 2A15A2M1. If

3-62. T-1654(P)/GRC-144V) and T-1054(P)A/ GRC-

a meter indication of 150 cannot be obtained, replace

144(V) Modulator Frequency Adjustment

the following components one at a time until a meter

indication of 150 is obtained: 70 MHz intermediate

Turn on Counter Electronic, Digital Readout

frequency amplifier 2A6, amplifier mixer 2A7, and

AM/USM-207 and allow a 1-minute warmup period.

tunnel diode amplifier 2A2. Replace the green cap over

On the AN/USM-207, set the controls as

the IF GAIN control on 2A5.

follows:

Turn off AN/URM-52B and disconnect RF

(1)

SENSITIVITY switch to PLUG-IN.

cable CG-92D/U from Coupler, Directional CU-

1890/GRC (fig. 3-W).

(2)

FUNCTION switch to FREQ.

Connect tile coaxial cable removed in step k

(3)

Time base switch to GATE TIME

-1

(SEC ) -10 .

to Coupler, Directional CU-1890/GRC.

(4) Upper and lower converter attenuator

Using a screwdriver, turn the ATTEN ADJ

switches to 100V MAX.

control on Coupler, Directional CU-1890/GRC

counterclockwise until mechanical stop is reached.

(5) DIRECT-HETERODYNE

switch

HETERODYNE.

Record

the

T-o054(P)/GRC

-I44(V)

operating frequency.

(6)

Mixing frequency selector switch to

100.

On T-1054(P)/GRC-144(V), set controls on

radio frequency bandpass filter 1FL3 and electrical

(7)

DISPLAY control to desired display

frequency synthesizer 1A14 controls to 4800 MHz.

time.

Turn the OUTPUT LEVEL switch on the

Disconnect coaxial cable 1A6W2 from the

radio test set to LOW.

J1 connector on radio transmitter modulator 1A8.

Set the ON/OFF switch on 100 MHz radio

Disconnect coaxial cable 1A8W1 from the

frequency oscillator 1A2 to ON.

A1J1 connector on transmitter frequency mixer stage

1A9.

Set the meter switch on the radio test set to

CR1. The radio test set meter indication shall be in or to

Connect the equipment as shown in view A,

the right of the yellow band.

figure 3-28. Note that the Tee connector is also

connected to A1J1 on 1A9.

aa. Set the meter switch on the radio test set to

CR2. The radio test set meter indication shall be in or to

the right of the yellow band.

Change 6

3-79