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not within 3.5 kc of 31.50 mc or until
Short
a frequency of 31.9.5 mc is reached.
(7)
Record the last RT-505/PRC-25 frequency
-------------------
Minimum
Test frequency (mc)
voltage
setting that produced an AN/USM-26
(rms)
(ohms)
(uff)
reading within 3.5 kc of 31.50 mc.
------------ -- --
-- -- ----------
Adjust RT-505/PRC-25 to 31.50 mc and
(8)
26.1
30.00------------------
12
4
repeat the procedures given in (3) through
56.2
18
52.50------------------
7
(7) above except reduce the frequency
5
56.2
18
53.50------------------
setting for each successive step until the
61.9
75.00------------------
82
7
output frequency exceeds 3.5 kc of 31.50
mc or until a frequency of 31.00 is reached.
(11) Set the test assembly TRANSMITTER
Withdraw the decoupling tool and engage
(9)
CARRIER switch to ON and read the
the coupling.
RF voltage across the resistor of the
Adjust the RT-505/PRC-25 to 51.50 mc
(l0)
and disengage the coupling ((2 above).
The minimum acceptable reading is listed
(11)
Repeat the procedures given in (3), (4),
in the chart in (10) above.
and (5) above until the AN/USM-26
(12) Set the test assembly TRANSMITTER
reading produced is not within 3.5 kc of
CARRIER switch to OFF.
51.50 mc or until a frequency of 51.95 mc is
(13) Repeat the procedures given in (10), (11),
reached.
and (12) above at 52..50, 53.50, and 75.00
(12)
mc. Use the chart in (10) above to corre-
Record the last RT-505/PRC-25 frequency
late test frequency, transmitter load, and
within 3.5 kc of 51.50 mc.
minimum acceptable voltage.
Adjust RT-505/PRC-25 to 51.50 mc and
(13)
repeat the procedures given in (3), (4), and
replace the screw in the corner of the whip
(5) above, except reduce the frequency for
ANT jack.
each successive step, check the AN/USM-
g. Catching Range Test.
26 for 51.50 mc 3.5 kc at each step, and
(1) Perform the catching range test with the
stop if 51.00 mc is reached. Record the
equipment connected in a standard trans-
limiting frequency.
mitter test setup (para 103 and fig. 79.8)
(14)
Withdraw the decoupling tool and engage
except set the HP-200AB output level to
zero and the RT-505/PRC-25 frequency
the coupling.
Evaluate the test results. At both test
(15)
to 31.50 mc. Set the RT-505/PRC-25
frequencies (31.50 and 51.50 me), the
upside-down for this test.
minimum acceptable catching range is 650
Caution: Check to see that the RT-505/
kc with at least 250 kc on each side of the
PRC-25 is set to a frequency ending in 50
test frequency.
( XX.50 ) when disengaging the coupling in
procedure in (2) below; otherwise the
h. Distortion Test.
coupling may become damaged.
(1) Perform the distortion test with the equip-
(2) Disengage the mechanical coupling finger
ment connected in a standard transmitter
(fig. 3, TM 11-5820-398-20) that disables
test setup (para 103 and fig. 79.8), except
the crystal switching assembly from module
connect test cable No. 1 from test point
Al0 (para 104e(2)).
A23J3 to chassis ground. The ME-57/U is
(3) Adjust the RT-505/PRC-25 to a frequency
used as a receiver for this test.
50-kc higher than its current setting.
(2) Set the test assembly TRANSMITTER
(4) Set the test assembly TRANSMITTER
CARRIER switch to ON.
CARRIER switch to ON and observe the
(3) Tune the ME-57/U for minimum distortion.
frequency indicated by the AN/USM-26.
(4) Read the distortion on the TS-723A/U.
it should be 31.50 mc 3.5 kc.
Maximum allowable distortion is 10 per-
(5) Set the test assembly TRANSMITTER
cent.
CARRIER switch to OFF.
(5) Set the test assembly TRANSMITTER
(6) Repeat the procedures given in (3), (4), and
CARRIER switch to OFF.
(5) above until the AN/USM-26 reading is
21
TAGO 8344-A

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