TM 11-6625-828-12
Switch or control
Position
uv control. Normally, the ATTEN output is used for
receiver testing and, under such circumstances, the 1
VOLT connector must be capped with the 51-ohm
POWER-STAND BY ----
STAND BY.
termination cap. This termination is necessary as the
30 - MOD ------------------
Fully counterclockwise.
ATTENUATOR uv control scale is calibrated to indicate
90 - MOD ------------------
Fully counterclockwise.
microvolts appearing across an external 51-ohm load
9960 - MOD ---------------
Fully counterclockwise.
when the 1VOLT connector is properly terminated.
150 - MOD-----------------
Fully counterclockwise.
RF LEVEL SET-----------
Fully counterclockwise.
NOTE
1000 - MOD ---------------
Fully counterclockwise.
If the receiver under test has an
MODULATION -----------
9960 ~.
impedance of other than 51 ohms,
IDENTIFIER---------------
OFF.
some method other than reading the
MC---------------------------
A.
ATTENUATOR uv control scale to
ATTENUATOR uv -------
Midscale.
determine the output voltage will be
required.
(1) Connect the 51-ohm termination to the RF
WARNING
OUTPUT 1 VOLT connector.
Dc voltages up to 75 volts appear
(2) Unscrew the crystal receptacle cover located
between
the
DEMOD
output
below the MC switch and check the frequency rating of
connector and ground. Be careful
the installed crystals. Insure that the panel frequency
when connecting the equipment
tabs agree with the crystal frequencies. The upper
under test.
crystal corresponds with the A position; the lower crystal
b.
Demodulated Output.
Modulation voltages
corresponds with the B position.
generated by the SG-66B/ARM-5 are made available for
(3) Connect Power Cable Assembly CX-337/U
bench test use through the DEMOD connector. The
between the SG-66-B/ARM-5 and a 115-volt, 60-cycle
output from the DEMOD connector is derived from the
power source. Allow the equipment to warm up for a
RF carrier and the demodulating circuits are designed so
minimum of 5 minutes.
that, when connected to a resistive load, the
NOTE
demodulated output will have the same wave shape and
Omnireceivers show course errors
phase as the modulation envelope. If the demodulated
when the modulation frequencies
output is connected to a reactive load, a phase shift will
deviate from 30 cycles. The 30-cycle
result which must considered when testing omni
frequency generated by the SG-
equipment. The demodulated output may be adjusted by
66B/ARM-5 is directly proportional to
means of a screwdriver adjustment, to the left of the
the
primary
power
frequency,
DEMOD connector, to any desired value within the limits
therefore, it is necessary that the
shown below.
primary power frequency be 60
b. Demodulated output (cont).
cycles and stable.
b. Starting. Set the POWER-STAND BY switch on
MODULATION
switch position
Condition
Approx volts (rms)
the front panel to POWER.
1000 ~
With 1000 - MOD con-
1.4 to 17
trol adjusted for
3-4. Operating Procedure
100%.
Operation of Test Set, Radio AN/ARM-5A is determined
9960~
With 9960 ~ MOD con-
0.5 to 6
by the requirements of the type of equipment under test,
trol set for 30%.
and the type of tests to be performed. The type of output
30~
With 30 - MOD con-
0.5 to 6
signal required from the SG-66B/ARM-5 will determine
trol set for 30%.
the setting and use of the front panel controls. The
AMP LOC
Normal adjustments.
0.5 to 6
OMNI
Normal adjustments.
0.6 to 8
different output signals available for testing are as
90~
With 90~ MOD con-
0.35 to 4
follows:
trol set for 20%.
a. RF Output. The radiofrequency (RF) output of the
150~
With 150 ~ MOD con-
0.35 to 4
SG-66B/ARM-5 is available at the RF OUTPUT ATTEN-
trol set for 20%.
and 1 VOLT connectors. A variable output of from 1 to
c. Modulated Output. The SG-66B/ARM-5 provides
10,000 microvolts is available at the ATTEN connector.
internal modulation for omni and ampli
This output has a source impedance of 51 ohms and is
adjustable continuously by means of the ATTENUATOR
3-3
