Receiver Sensitivity Tests

TM 11-5820-509-35

4-6. Receiver Sensitivity Tests

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

(fig. 4-1)

single-phase, 3 amps.

26.5-volt, dc, 11 amperes

NOTE

approx.

This test must be performed in a

b. Test Conditions and Equipment Connections.

screen-room similar to Electro-

(1) Connect the test equipment to Radio

Magnetic Shielding Enclosure MX-

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

1766/G or equal.

figure 4-1.

(2) Connect the 115-volt primary power

a. Test Equipment and Material.

source to the receiver-transmitter.

(1) Signal Generator SC-103/URM-25F.

(3) Turn on the test equipment and place the

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

(2) Frequency Counter AN/URM-79/U.

ON. Permit the equipment to stabilize for at least 6

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

minutes before beginning the procedures shown in the

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

chart below.

resistor.

(5) Coaxial tee, UG-274B/U.

Figure 4-1. Receiver Sensitivity, AVC Selectivity, IF. Rejection,

Image Rejection, and Volume Control Tests, Equipment Setup.

c. Procedure After each adjustment of the

output frequency to the newly selected transmitter

frequency control knobs on the front panel of the

operating frequency, plus 1 kHz, and reset the output

receiver-transmitter, readjust the signal generator

level to the required value.

Test

Radio

equipment

control

Test

Performance

Step

settings

procedures

standards

Adjustsignalgeneratorto2226kHz;

Adjustfrequencycontrolknobs

Readaudiooutputvoltage

Minimum accept ablevoltageof1.9voltsrms.

kHz;setoutputlevelto2.0

to2225onKILOCYCLES

across300-ohmaudioload.

of3.9voltsrms

microvolts.

indicatorCW-FSK/VOICE to

Disconnectsignal generator

Maximumacceptablevoltage1.25voltsrms.

VOICE;OPR-TUNEto

fromANTENNAterminal

1.25voltsrms.

Tomaximumclockwisestop.

Across300-ohmaudioload.

Change 1 4-2