TM9-4935-294-15/2
3-11.
Operational Check and Troubleshooting
3-12.
Operational Check and Troubleshooting
of VSWR Measurement Setup
of Attenuation Measurement Setups.
a. Preliminary Procedures.
Below 1 GHz.
a Preliminary Procedures.
(1)
Set up equipment as shown in the
appropriate figure illustrating the setup for attenuation
(1)
Set up equipment as shown in the figure
measurement in chapter 2, section III, of TM 9-4981-
illustrating the setup for VSWR measurement between
294-15/1. Select the setup in accordance with the
0.5 and 1 GHz in chapter 2, section III, of TM 9-4981-
frequency at which the attenuation measurement is to be
294-15/1.
performed.
(2) Set the SWR meter controls as follows:
(2)
Adjust both level-set attenuators in test
setup for maximum attenuation.
(a) POWER switch to LINE OFF.
(3)
Set microwave receiver controls as follows:
(b) RANGE-DB switch to 20.
(a) POWER LEVEL control to mid-range.
(c) EXPAND switch to NORMAL.
(b) NOISE BALANCE control fully ccw.
(d) INPUT switch to XTAL IMPED
(c) ZERO-NORMAL switch to NORMAL.
BIASED LOW.
(d) XTAL-AFC switch to XTAL.
(e) GAIN and VERNIER controls mid-
(e) AFC OFF-AFC ON switch to AFC OFF.
position.
(f) AGC VOLTS-VIDEO LEVEL switch to
(f) If meter needle does not rest over
VIDEO LEVEL.
calibration mark (2 on 0-2 DB scale), rotate meter
(4)
Energize all equipment in the test setup and
mechanical zero adjustment cw until meter pointer is to
allow approx. 30 minutes for equipment to warm up and
the left of 2 (on 0-2 DB scale). Continue to rotate
stabilize.
adjustment cw as the needle move to the right, stopping
b. Operational Check and Troubleshooting Chart. After
when the needle is exactly on 2.
performing the preliminary procedures described in a
above, proceed with the steps of table 8-9. For
b. Operational Check and Troubleshooting
Chart.
complete operational procedures, refer to the paragraph
After performing preliminary procedures described in a
on attenuation measurement in chapter 2, section III, of
above, proceed with the steps of table 3-8. For
TM 9-4981-294-15/1.
complete operational procedures, refer to the paragraph
on VSWR measurement in the frequency range from 0.5
to 1 GHz in chapter 2, section III, of TM 9-4981-294-
15/1.
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