RECEIVER SELECTIVITY TEST. - TM-11-5820-401-34-30394

TM 11-5820-401-34-3/0967-LP-432-3060

RECEIVER SELECTIVITY TEST.

5-10.

PURPOSE. This test checks the ability of the R-442/VRC A4000 tray IF Filters FL4001 and FL4002, to

reject unwanted signals and, thus, determine bandwidth. The R-442/VRC should have a minimum

bandwidth of 32 kHz at the filters' 6-db attenuation point and a maximum bandwidth of 80 kHz at their

60-db attenuation point. This is verified by:

1. Finding the minimum rf level which must be Injected Into the R-442/VRC ANTENNA port to

cause the CALL lamp to light.

2. Injecting twice the rf level found in step 1, while observing that the R-442/VRC CALL

lamp Is Ilt when the frequency Is offset 16 kHz from the carrier.

3. Injecting 1000 times the rf level found in step 1, while observing that the R-442/VRC

CALL lamp is off when the frequency Is offset more than t 40 kHz from the carrier.

TEST EQUIPMENT AND MATERIALS

Adapter (T-Connector) UG-274 B/U

Power Supply PP-1104(*)/G

Matching Unit CN-901/U

Frequency Counter AN/USM-207

Rf Cables (two) RG-58/U

Signal Generator ANWRM-103

Test Cable No. 1

Loudspeaker LS-454/U

TEST SETUP. Connect equipment as shown in test setup diagram

Turn on test equipment. Allow at least 15 to 30 minutes for warmup.

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