Transmitter Sidetone Adjustment

TM 11-5820-509-35

Figure 3-107. Receiver AGC Circuit Adjustment, Test Equipment Setup.

controls are being adjusted. Circuit

3-24. Transmitter Sidetone Adjustment

(fig. 3-94, 3-108)

damage can occur.

a. Preliminary Procedures.

(6) Set the POWER AMPLIFIER LOAD and

POWER AMPLIFIER TUNE controls to the turns

counter values shown on the LOAD-TUNE chart; then

(1) Remove the RT-671/PRC-47 from its

place the OPR-TUNE switch to TUNE and quickly peak

case using the procedures of paragraph 3-11.

the load and tune controls for maximum deflection of

(2) Connect the primary power source to the

the XMTR OUTPUT meter.

POWER connector on the front panel of RT-671 /PRC-

47.

NOTE

(3) Connect the output meter and dummy

Adjust M ADJ control as required to

load to the receiver-transmitter as shown in figure 3-108.

maintain the XMTR OUTPUT meter

(4) Set the output meter IMPEDANCE switch

pointer on a useful portion of the

to 300 ohms, and adjust the meter multiplier for 500

scale.

milliwatts full scale.

(5) On the front panel of RT-671/PRC-47, set

the controls as follows:

(7) Return the OPR-TUNE switch to OPR and

set XMTR PWR switch to HI.

(a)

KILOCYCLES indicator to 2000.

(8) Again place the OPR-TUNE switch to

(b)

CW-FSK/VOICE switch to VOICE.

TUNE and peak the POWER AMPLIFIER LOAD and

(c)

OPR-TUNE switch to OPR.

POWER AMPLIFIER TUNE controls as necessary for

maximum XMTR OUTPUT meter deflection.

(d)

XMTR PWR switch to LO.

(e)

VOLUME control to maximum

clock-wise stop.

b. Adjustment Procedures.

(f)

POWER-LIGHTS switch to POWER

ON.

(1) Observe the output meter and adjust

A1R46 (fig. 3-94) to obtain a reading of 100 milliwatts

CAUTION

(5.5 volts in 300 ohms).

Do not permit the OPR-TUNE switch

(2) Return the XMTR PWR switch to OFF,

to remain in the TUNE position for

the POWER-LIGHTS switch to POWER OFF, and

more than a few seconds at a time

disconnect the test equipment.

while the POWER AMPLIFIER TUNE

(3) Return the RT-671/PRC-47 to its case

and POWER AMPLIFIER LOAD

using the procedures of paragraph 3-11 if no further

adjustments are required.

3-126