RECEIVER SELECTIVITY TEST. - TM-11-5820-401-34-30242

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

4-10. RECEIVER SELECTIVITY TEST.

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

60db 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 lit when the frequency is offset k 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 40 kHz from the carrier.

TEST EQUIPMENT AND MATERIALS

Power Supply PP-1104(*)/G

Test Set AN/GRM-114A

Maintenance Klt MK-1978/VRC

Rf Cable RG-58/U

TEST SETUP. Connect equipment as shown in test setup diagram

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