Transmitter Hum Balance Adjustment

TM 11-5820-509-35

and adjustments, resonate the POWER

c. Procedure.

AMPLIFIER TUNE and POWER AMPLIFIER

(1) On the RT-671/PRC-47, set the

LOAD controls on the front of the receiver-

KILOCYCLES indicator to 11000; place the CW-

transmitter for maximum deflection on the

FSK/VOICE switch to VOICE, XMTR PWR switch to LO,

XMTR OUTPUT meter. Use the OPR-TUNE

and OPR-TUNE switch to OPR.

switch to control power amplifier plate power.

(2) Place the turns-counters of POWER

Do not permit the power amplifier to operate

AMPLIFIER TUNE and POWER AMPLIFIER LOAD

for more than a few seconds in the unloaded

controls to the settings recommended on the LOAD-

condition, serious damage to the equipment

TUNE chart on the front of the receiver- transmitter .

can result.

CAUTION

Before making the following measurements

Test

Radio

equipment

control

Test

Performance

Step

settings

procedures

standards

Set spectrum analyzer to

Resonate power amplifier

Adjust transmit mixer

Adjust for minimum

11,000 kHz.

with XMTR PWR switch

balance pot A3R150

analyzer reading.

at HI.

(fig. 3 95).

Same as step 1

Immediately return OPR

Not applicable.

TUNE switch to OPR.

Set multimeter to RF VOLTS,

Place OPR-TUNE switch

Adjust transmit gain

Continue to adjust until

and connect the rf

again to TUNE

control A3R148 (fig. 3-95)

meter indication stops

probe to J104 (fig.. 3 99).

clockwise.

rising.

5-5. Transmitter Hum Balance Adjustment

b. Test Conditions and Equipment Connections.

(fig. 5-2)

(1) Connect the test equipment to Radio

a. Test Equipment and Material.

Receiver-Transmitter RT-671/PRC-47 as shown in

figure 5-2. Do not connect ME-26A/U until instructed to

(1) Spectrum Analyzer AN/UPM-110

do so.

(2) Converter. Hewlett-Packard K15-8551B

(2) Connect the primary power source to the

(3) Dummy Load NA-75/U

receiver-transmitter.

(4) Attenuator (see fig. 5-2).

(3) Turn on the test equipment and place the

(5) Multimeter ME-26A/U

POWER-LIGHTS switch on the RT-671/PRC-47 to

(6) Audio Oscillator TS-382/U

POWER ON. Permit the equipment to stabilize for at

(7) Primary power source: 115-volt, 400-Hz,

least 5 minutes before beginning the procedures listed in

single-phase, 3 amp.

the chart below.

5-2