Figure 5-3. VSWR test setup diagram.

TM 11-5985-335-15

Test Procedure.

(1) Insure that there are no obstructions within 500 feet of the AS-1425/GRC. If necessary, tilt the antenna

above the horizon to clear obstructions.

(2) Make the test connections shown in figure 54, connecting the output flange of the IM-100/100-37( ) to the

input end of the CG-3307/GRC and the waveguide flange of the UG-1054/u to the input flange of the IM-100/USM47( ).

(3) Turn on the AN/URM-52( ) and the AN/USM-37( ), and allow the warm-up periods specified in the test

equipment manuals.

(4) Adjust the AN/URM42( ) controls for 4.4 GHz at 1 milliwatt (mw) output. Set controls at 1000 Hz square

wave modulation.

(5) The VSWR should not exceed 1.2 to 1 as measured on the AN/USM-37( ).

(6) Set the AN/URM-52( ) output frequency at 4.7 GHz, maintaining the 1-mw output level.

(7) The VSWR should not exceed 1.2 to 1.

(8) Set the AN/URM-52( ) output frequency at 5.0 GHz, maintaining the 1-mw output level.

(9) The VSWR should not exceed 1.2 to 1.

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