Transmitter Sidetone Test

TM 1 1-5820-509-35

4-19. Transmitter Sidetone Test

c. Procedure.

(fig. 4-7)

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

a. Test Equipment and Material.

KILOCYCLES indicator to 2000; set CW-FSK/VOICE

(1) Spectrum Analyzer TS-723A/U.

switch to VOICE, the XMTR PWR switch to LO, and the

OPR-TUNE switch to OAR.

(2) Dummy Load DA-75/U.

(2) Place the turns-counters of POWER

(3) Telegraph Key J-45.

AMPLIFIER TUNE and POWER AMPLIFIER LOAD

(4) Audio load, 300-ohm, 1-watt compos-

controls on the front panel of RT-671/PRC-47 to the

ition resistor.

settings recommended on the LOAD-TUNE! chart.

(5) Primary power source: 26.5-volt, dc,

CAUTION

11 amperes approx.

Before

making

the

following

b. Test Conditions and Equipment Connections.

measurements, resonate the POWER

(1) Connect the test equipment to Radio

AMPLIFIER TUNE and POWER

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

AMPLIFIER LOAD controls on the

figure 4-7.

front

panel

the

receiver-

(2) Connect the primary power source to the

transmitter. for maximum deflection

receiver-transmitter.

on the XMTR PWR meter. Use the

(3) Turn on the test equipment and place the

OPR-TUNE switch to control power

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

amplifier plate power. Do not permit

ON. Permit the equipment to stabilize for at least 5

the power amplifier to operate for

minutes before beginning the procedures shown in the

more than a few seconds at a time in

chart below.

the

unloaded

off-resonant

condition,

serious

equipment

damage can result.

Test

Radio

equipment

control

Test

Performance

Step

settings

procedures

standards

Set meter range switch to 10

Place XMTR PWR switch to HI

Hold telegraph key closed and

Meter reads not less than 3.9 volts

VOLTS R.M.S.

and peak the power amplifier;

measure voltage across 300-

rms.

return OPR-TUNE to OPR, an

ohmn audio load

switch C W-FSK/VOICE switch

to C'W-ISK; set VOLUME

control to maximum clockwise

stop.

Same as step 1.

Same as step 1, except set

Same as step 1.

KILOCY('LI:S indicator to

11999. Resonate the power

amplifier output circuit with

XMTR PWR switch at LO

and then at HI.

Change 1 4-18